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* compiler: remove __ADDRESSABLE_ASM{_STR,}() againJan Beulich2025-08-181-2/+3
| | | | | | | | | | | | | | | | | | | | | __ADDRESSABLE_ASM_STR() is where the necessary stringification happens. As long as "sym" doesn't contain any odd characters, no quoting is required for its use with .quad / .long. In fact the quotation gets in the way with gas 2.25; it's only from 2.26 onwards that quoted symbols are half-way properly supported. However, assembly being different from C anyway, drop __ADDRESSABLE_ASM_STR() and its helper macro altogether. A simple .global directive will suffice to get the symbol "declared", i.e. into the symbol table. While there also stop open-coding STATIC_CALL_TRAMP() and STATIC_CALL_KEY(). Fixes: 0ef8047b737d ("x86/static-call: provide a way to do very early static-call updates") Signed-off-by: Jan Beulich <[email protected]> Acked-by: Josh Poimboeuf <[email protected]> Cc: [email protected] Signed-off-by: Juergen Gross <[email protected]> Message-ID: <[email protected]>
* objtool: Fix X86_FEATURE_SMAP alternative handlingJosh Poimboeuf2025-03-251-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For X86_FEATURE_SMAP alternatives which replace NOP with STAC or CLAC, uaccess validation skips the NOP branch to avoid following impossible code paths, e.g. where a STAC would be patched but a CLAC wouldn't. However, it's not safe to assume an X86_FEATURE_SMAP alternative is patching STAC/CLAC. There can be other alternatives, like static_cpu_has(), where both branches need to be validated. Fix that by repurposing ANNOTATE_IGNORE_ALTERNATIVE for skipping either original instructions or new ones. This is a more generic approach which enables the removal of the feature checking hacks and the insn->ignore bit. Fixes the following warnings: arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8ec: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8f1: unreachable instruction [ mingo: Fix up conflicts with recent x86 changes. ] Fixes: ea24213d8088 ("objtool: Add UACCESS validation") Reported-by: kernel test robot <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Cc: Linus Torvalds <[email protected]> Link: https://lore.kernel.org/r/de0621ca242130156a55d5d74fed86994dfa4c9c.1742852846.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
* x86/xen: remove hypercall pageJuergen Gross2024-12-171-2/+0
| | | | | | | | | | | | | | | | The hypercall page is no longer needed. It can be removed, as from the Xen perspective it is optional. But, from Linux's perspective, it removes naked RET instructions that escape the speculative protections that Call Depth Tracking and/or Untrain Ret are trying to achieve. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Reviewed-by: Andrew Cooper <[email protected]> Reviewed-by: Jan Beulich <[email protected]>
* x86/xen: use new hypercall functions instead of hypercall pageJuergen Gross2024-12-171-13/+20
| | | | | | | | | | | | Call the Xen hypervisor via the new xen_hypercall_func static-call instead of the hypercall page. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Co-developed-by: Peter Zijlstra <[email protected]> Co-developed-by: Josh Poimboeuf <[email protected]>
* x86/xen: add central hypercall functionsJuergen Gross2024-12-171-0/+3
| | | | | | | | | | | | | | | | | | | | | | Add generic hypercall functions usable for all normal (i.e. not iret) hypercalls. Depending on the guest type and the processor vendor different functions need to be used due to the to be used instruction for entering the hypervisor: - PV guests need to use syscall - HVM/PVH guests on Intel need to use vmcall - HVM/PVH guests on AMD and Hygon need to use vmmcall As PVH guests need to issue hypercalls very early during boot, there is a 4th hypercall function needed for HVM/PVH which can be used on Intel and AMD processors. It will check the vendor type and then set the Intel or AMD specific function to use via static_call(). This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Co-developed-by: Peter Zijlstra <[email protected]>
* cpuidle, xenpv: Make more PARAVIRT_XXL noinstr cleanPeter Zijlstra2023-01-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | objtool found a few cases where this code called out into instrumented code: vmlinux.o: warning: objtool: acpi_idle_enter_s2idle+0xde: call to wbinvd() leaves .noinstr.text section vmlinux.o: warning: objtool: default_idle+0x4: call to arch_safe_halt() leaves .noinstr.text section vmlinux.o: warning: objtool: xen_safe_halt+0xa: call to HYPERVISOR_sched_op.constprop.0() leaves .noinstr.text section Solve this by: - marking arch_safe_halt(), wbinvd(), native_wbinvd() and HYPERVISOR_sched_op() as __always_inline(). - Explicitly uninlining xen_safe_halt() and pv_native_wbinvd() [they were already uninlined by the compiler on use as function pointers] and annotating them as 'noinstr'. - Annotating pv_native_safe_halt() as 'noinstr'. Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Tested-by: Tony Lindgren <[email protected]> Tested-by: Ulf Hansson <[email protected]> Reviewed-by: Srivatsa S. Bhat (VMware) <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Acked-by: Rafael J. Wysocki <[email protected]> Acked-by: Frederic Weisbecker <[email protected]> Link: https://lore.kernel.org/r/[email protected]
* xen: make HYPERVISOR_set_debugreg() always_inlineJuergen Gross2021-11-251-1/+1
| | | | | | | | | | | | HYPERVISOR_set_debugreg() is being called from noinstr code, so it should be attributed "always_inline". Fixes: 7361fac0465ba96ec8f ("x86/xen: Make set_debugreg() noinstr") Reported-by: kernel test robot <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Boris Ostrovsky <[email protected]>
* xen: make HYPERVISOR_get_debugreg() always_inlineJuergen Gross2021-11-251-1/+1
| | | | | | | | | | | | HYPERVISOR_get_debugreg() is being called from noinstr code, so it should be attributed "always_inline". Fixes: f4afb713e5c3a4419ba ("x86/xen: Make get_debugreg() noinstr") Reported-by: kernel test robot <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Boris Ostrovsky <[email protected]>
* xen: allow pv-only hypercalls only with CONFIG_XEN_PVJuergen Gross2021-11-021-109/+102
| | | | | | | | | | | | | | Put the definitions of the hypercalls usable only by pv guests inside CONFIG_XEN_PV sections. On Arm two dummy functions related to pv hypercalls can be removed. While at it remove the no longer supported tmem hypercall definition. Signed-off-by: Juergen Gross <[email protected]> Link: https://lore.kernel.org/r/[email protected] Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
* x86/xen: remove 32-bit pv leftoversJuergen Gross2021-11-021-30/+8
| | | | | | | | | | There are some remaining 32-bit pv-guest support leftovers in the Xen hypercall interface. Remove them. Signed-off-by: Juergen Gross <[email protected]> Link: https://lore.kernel.org/r/[email protected] Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
* x86/xen: Mark xen_force_evtchn_callback() noinstrPeter Zijlstra2021-09-171-1/+1
| | | | | | | | vmlinux.o: warning: objtool: check_events()+0xd: call to xen_force_evtchn_callback() leaves .noinstr.text section Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Link: https://lore.kernel.org/r/[email protected]
* x86/xen: Make set_debugreg() noinstrPeter Zijlstra2021-09-171-1/+1
| | | | | | | | | | vmlinux.o: warning: objtool: pv_ops[2]: xen_set_debugreg vmlinux.o: warning: objtool: pv_ops[2]: native_set_debugreg vmlinux.o: warning: objtool: exc_debug()+0x3b: call to pv_ops[2]() leaves .noinstr.text section Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Link: https://lore.kernel.org/r/[email protected]
* x86/xen: Make get_debugreg() noinstrPeter Zijlstra2021-09-171-1/+1
| | | | | | | | | | vmlinux.o: warning: objtool: pv_ops[1]: xen_get_debugreg vmlinux.o: warning: objtool: pv_ops[1]: native_get_debugreg vmlinux.o: warning: objtool: exc_debug()+0x25: call to pv_ops[1]() leaves .noinstr.text section Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Link: https://lore.kernel.org/r/[email protected]
* xen: hypercall.h: fix duplicated wordRandy Dunlap2020-08-031-1/+1
| | | | | | | | | | | | Change the repeated word "as" to "as a". Signed-off-by: Randy Dunlap <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Cc: Boris Ostrovsky <[email protected]> Cc: Juergen Gross <[email protected]> Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Juergen Gross <[email protected]>
* mm: reorder includes after introduction of linux/pgtable.hMike Rapoport2020-06-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s <file> <header>" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include <linux/%s>" % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include <linux/"): in_hdrs = True elif not moved and in_hdrs: moved = True print hdr_to_move print line Signed-off-by: Mike Rapoport <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Cain <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chris Zankel <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Greentime Hu <[email protected]> Cc: Greg Ungerer <[email protected]> Cc: Guan Xuetao <[email protected]> Cc: Guo Ren <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Helge Deller <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Ley Foon Tan <[email protected]> Cc: Mark Salter <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Matt Turner <[email protected]> Cc: Max Filippov <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Michal Simek <[email protected]> Cc: Nick Hu <[email protected]> Cc: Paul Walmsley <[email protected]> Cc: Richard Weinberger <[email protected]> Cc: Rich Felker <[email protected]> Cc: Russell King <[email protected]> Cc: Stafford Horne <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Luck <[email protected]> Cc: Vincent Chen <[email protected]> Cc: Vineet Gupta <[email protected]> Cc: Will Deacon <[email protected]> Cc: Yoshinori Sato <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
* mm: introduce include/linux/pgtable.hMike Rapoport2020-06-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Cain <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Chris Zankel <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Greentime Hu <[email protected]> Cc: Greg Ungerer <[email protected]> Cc: Guan Xuetao <[email protected]> Cc: Guo Ren <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Helge Deller <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Ley Foon Tan <[email protected]> Cc: Mark Salter <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Matt Turner <[email protected]> Cc: Max Filippov <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Michal Simek <[email protected]> Cc: Nick Hu <[email protected]> Cc: Paul Walmsley <[email protected]> Cc: Richard Weinberger <[email protected]> Cc: Rich Felker <[email protected]> Cc: Russell King <[email protected]> Cc: Stafford Horne <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tony Luck <[email protected]> Cc: Vincent Chen <[email protected]> Cc: Vineet Gupta <[email protected]> Cc: Will Deacon <[email protected]> Cc: Yoshinori Sato <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
* Merge branch 'core-objtool-for-linus' of ↵Linus Torvalds2019-05-061-4/+20
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: "This is a series from Peter Zijlstra that adds x86 build-time uaccess validation of SMAP to objtool, which will detect and warn about the following uaccess API usage bugs and weirdnesses: - call to %s() with UACCESS enabled - return with UACCESS enabled - return with UACCESS disabled from a UACCESS-safe function - recursive UACCESS enable - redundant UACCESS disable - UACCESS-safe disables UACCESS As it turns out not leaking uaccess permissions outside the intended uaccess functionality is hard when the interfaces are complex and when such bugs are mostly dormant. As a bonus we now also check the DF flag. We had at least one high-profile bug in that area in the early days of Linux, and the checking is fairly simple. The checks performed and warnings emitted are: - call to %s() with DF set - return with DF set - return with modified stack frame - recursive STD - redundant CLD It's all x86-only for now, but later on this can also be used for PAN on ARM and objtool is fairly cross-platform in principle. While all warnings emitted by this new checking facility that got reported to us were fixed, there might be GCC version dependent warnings that were not reported yet - which we'll address, should they trigger. The warnings are non-fatal build warnings" * 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits) mm/uaccess: Use 'unsigned long' to placate UBSAN warnings on older GCC versions x86/uaccess: Dont leak the AC flag into __put_user() argument evaluation sched/x86_64: Don't save flags on context switch objtool: Add Direction Flag validation objtool: Add UACCESS validation objtool: Fix sibling call detection objtool: Rewrite alt->skip_orig objtool: Add --backtrace support objtool: Rewrite add_ignores() objtool: Handle function aliases objtool: Set insn->func for alternatives x86/uaccess, kcov: Disable stack protector x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP x86/uaccess, ubsan: Fix UBSAN vs. SMAP x86/uaccess, kasan: Fix KASAN vs SMAP x86/smap: Ditch __stringify() x86/uaccess: Introduce user_access_{save,restore}() x86/uaccess, signal: Fix AC=1 bloat x86/uaccess: Always inline user_access_begin() x86/uaccess, xen: Suppress SMAP warnings ...
| * x86/uaccess, xen: Suppress SMAP warningsPeter Zijlstra2019-04-031-4/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | drivers/xen/privcmd.o: warning: objtool: privcmd_ioctl()+0x1414: call to hypercall_page() with UACCESS enabled Some Xen hypercalls allow parameter buffers in user land, so they need to set AC=1. Avoid the warning for those cases. Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Signed-off-by: Ingo Molnar <[email protected]>
* | xen: Prevent buffer overflow in privcmd ioctlDan Carpenter2019-04-051-0/+3
|/ | | | | | | | | | | | | The "call" variable comes from the user in privcmd_ioctl_hypercall(). It's an offset into the hypercall_page[] which has (PAGE_SIZE / 32) elements. We need to put an upper bound on it to prevent an out of bounds access. Cc: [email protected] Fixes: 1246ae0bb992 ("xen: add variable hypercall caller") Signed-off-by: Dan Carpenter <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Juergen Gross <[email protected]>
* xen: remove pre-xen3 fallback handlersArnd Bergmann2019-03-051-11/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The legacy hypercall handlers were originally added with a comment explaining that "copying the argument structures in HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local variable is sufficiently safe" and only made sure to not write past the end of the argument structure, the checks in linux/string.h disagree with that, when link-time optimizations are used: In function 'memcpy', inlined from 'pirq_query_unmask' at drivers/xen/fallback.c:53:2, inlined from '__startup_pirq' at drivers/xen/events/events_base.c:529:2, inlined from 'restore_pirqs' at drivers/xen/events/events_base.c:1439:3, inlined from 'xen_irq_resume' at drivers/xen/events/events_base.c:1581:2: include/linux/string.h:350:3: error: call to '__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter __read_overflow2(); ^ Further research turned out that only Xen 3.0.2 or earlier required the fallback at all, while all versions in use today don't need it. As far as I can tell, it is not even possible to run a mainline kernel on those old Xen releases, at the time when they were in use, only a patched kernel was supported anyway. Fixes: cf47a83fb06e ("xen/hypercall: fix hypercall fallback code for very old hypervisors") Reviewed-by: Boris Ostrovsky <[email protected]> Cc: Jan Beulich <[email protected]> Signed-off-by: Arnd Bergmann <[email protected]> Signed-off-by: Juergen Gross <[email protected]>
* xen: remove unused hypercall functionsJuergen Gross2018-08-201-118/+0
| | | | | | | Remove Xen hypercall functions which are used nowhere in the kernel. Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
* xen: don't use privcmd_call() from xen_mc_flush()Juergen Gross2018-08-071-6/+19
| | | | | | | | | | | | | | | Using privcmd_call() for a singleton multicall seems to be wrong, as privcmd_call() is using stac()/clac() to enable hypervisor access to Linux user space. Even if currently not a problem (pv domains can't use SMAP while HVM and PVH domains can't use multicalls) things might change when PVH dom0 support is added to the kernel. Reported-by: Jan Beulich <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Reviewed-by: Jan Beulich <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
* x86/retpoline/xen: Convert Xen hypercall indirect jumpsDavid Woodhouse2018-01-111-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | Convert indirect call in Xen hypercall to use non-speculative sequence, when CONFIG_RETPOLINE is enabled. Signed-off-by: David Woodhouse <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Arjan van de Ven <[email protected]> Acked-by: Ingo Molnar <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Cc: [email protected] Cc: Rik van Riel <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: [email protected] Cc: Peter Zijlstra <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Kees Cook <[email protected]> Cc: Tim Chen <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Paul Turner <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
* Merge tag 'for-linus-4.14c-rc3-tag' of ↵Linus Torvalds2017-09-291-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from Juergen Gross: - avoid a warning when compiling with clang - consider read-only bits in xen-pciback when writing to a BAR - fix a boot crash of pv-domains * tag 'for-linus-4.14c-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/mmu: Call xen_cleanhighmap() with 4MB aligned for page tables mapping xen-pciback: relax BAR sizing write value check x86/xen: clean up clang build warning
| * x86/xen: clean up clang build warningColin Ian King2017-09-211-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | In the case where sizeof(maddr) != sizeof(long) p is initialized and never read and clang throws a warning on this. Move declaration of p to clean up the clang build warning: warning: Value stored to 'p' during its initialization is never read Signed-off-by: Colin Ian King <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
* | x86/asm: Fix inline asm call constraints for ClangJosh Poimboeuf2017-09-231-3/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For inline asm statements which have a CALL instruction, we list the stack pointer as a constraint to convince GCC to ensure the frame pointer is set up first: static inline void foo() { register void *__sp asm(_ASM_SP); asm("call bar" : "+r" (__sp)) } Unfortunately, that pattern causes Clang to corrupt the stack pointer. The fix is easy: convert the stack pointer register variable to a global variable. It should be noted that the end result is different based on the GCC version. With GCC 6.4, this patch has exactly the same result as before: defconfig defconfig-nofp distro distro-nofp before 9820389 9491555 8816046 8516940 after 9820389 9491555 8816046 8516940 With GCC 7.2, however, GCC's behavior has changed. It now changes its behavior based on the conversion of the register variable to a global. That somehow convinces it to *always* set up the frame pointer before inserting *any* inline asm. (Therefore, listing the variable as an output constraint is a no-op and is no longer necessary.) It's a bit overkill, but the performance impact should be negligible. And in fact, there's a nice improvement with frame pointers disabled: defconfig defconfig-nofp distro distro-nofp before 9796316 9468236 9076191 8790305 after 9796957 9464267 9076381 8785949 So in summary, while listing the stack pointer as an output constraint is no longer necessary for newer versions of GCC, it's still needed for older versions. Suggested-by: Andrey Ryabinin <[email protected]> Reported-by: Matthias Kaehlcke <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Dmitriy Vyukov <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Miguel Bernal Marin <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Link: http://lkml.kernel.org/r/3db862e970c432ae823cf515c52b54fec8270e0e.1505942196.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <[email protected]>
* x86/asm: Replace access to desc_struct:a/b fieldsThomas Gleixner2017-08-291-2/+4
| | | | | | | | | | | | | | | | | | | | | | The union inside of desc_struct which allows access to the raw u32 parts of the descriptors. This raw access part is about to go away. Replace the few code parts which access those fields. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Steven Rostedt <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
* x86/xen: allow userspace access during hypercallsMarek Marczykowski-Górecki2017-07-031-1/+8
| | | | | | | | | | | | | | | Userspace application can do a hypercall through /dev/xen/privcmd, and some for some hypercalls argument is a pointers to user-provided structure. When SMAP is supported and enabled, hypervisor can't access. So, lets allow it. The same applies to HYPERVISOR_dm_op, where additionally privcmd driver carefully verify buffer addresses. Cc: [email protected] Signed-off-by: Marek Marczykowski-Górecki <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Signed-off-by: Juergen Gross <[email protected]>
* xen: fix HYPERVISOR_dm_op() prototypeSergey Dyasli2017-06-081-1/+3
| | | | | | | | | | Change the third parameter to be the required struct xen_dm_op_buf * instead of a generic void * (which blindly accepts any pointer). Signed-off-by: Sergey Dyasli <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Reviewed-by: Stefano Stabellini <[email protected]> Signed-off-by: Juergen Gross <[email protected]>
* xen/privcmd: Add IOCTL_PRIVCMD_DM_OPPaul Durrant2017-02-141-0/+7
| | | | | | | | | | | | | | | | | | | | Recently a new dm_op[1] hypercall was added to Xen to provide a mechanism for restricting device emulators (such as QEMU) to a limited set of hypervisor operations, and being able to audit those operations in the kernel of the domain in which they run. This patch adds IOCTL_PRIVCMD_DM_OP as gateway for __HYPERVISOR_dm_op. NOTE: There is no requirement for user-space code to bounce data through locked memory buffers (as with IOCTL_PRIVCMD_HYPERCALL) since privcmd has enough information to lock the original buffers directly. [1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=524a98c2 Signed-off-by: Paul Durrant <[email protected]> Acked-by: Stefano Stabellini <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
* x86/xen: Add stack frame dependency to hypercall inline asm callsJosh Poimboeuf2016-02-241-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a hypercall is inlined at the beginning of a function, gcc can insert the call instruction before setting up a stack frame, which breaks frame pointer convention if CONFIG_FRAME_POINTER is enabled and can result in a bad stack trace. Force a stack frame to be created if CONFIG_FRAME_POINTER is enabled by listing the stack pointer as an output operand for the hypercall inline asm statements. Signed-off-by: Josh Poimboeuf <[email protected]> Reviewed-by: David Vrabel <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Bernd Petrovitsch <[email protected]> Cc: Boris Ostrovsky <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Chris J Arges <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Michal Marek <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Pedro Alves <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/c6face5a46713108bded9c4c103637222abc4528.1453405861.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <[email protected]>
* xen: rename dom0_op to platform_opStefano Stabellini2015-12-211-3/+3
| | | | | | | | | The dom0_op hypercall has been renamed to platform_op since Xen 3.2, which is ancient, and modern upstream Linux kernels cannot run as dom0 and it anymore anyway. Signed-off-by: Stefano Stabellini <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]>
* xen: use correct type for HYPERVISOR_memory_op()Juergen Gross2015-09-281-2/+2
| | | | | | | | | | | | | | HYPERVISOR_memory_op() is defined to return an "int" value. This is wrong, as the Xen hypervisor will return "long". The sub-function XENMEM_maximum_reservation returns the maximum number of pages for the current domain. An int will overflow for a domain configured with 8TB of memory or more. Correct this by using the correct type. Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: David Vrabel <[email protected]>
* xen/PMU: Sysfs interface for setting Xen PMU modeBoris Ostrovsky2015-08-201-0/+6
| | | | | | | | Set Xen's PMU mode via /sys/hypervisor/pmu/pmu_mode. Add XENPMU hypercall. Signed-off-by: Boris Ostrovsky <[email protected]> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]> Signed-off-by: David Vrabel <[email protected]>
* arm: xen: implement multicall hypercall support.Ian Campbell2014-04-241-1/+1
| | | | | | | | | | | | | | | | | | | | As part of this make the usual change to xen_ulong_t in place of unsigned long. This change has no impact on x86. The Linux definition of struct multicall_entry.result differs from the Xen definition, I think for good reasons, and used a long rather than an unsigned long. Therefore introduce a xen_long_t, which is a long on x86 architectures and a signed 64-bit integer on ARM. Use uint32_t nr_calls on x86 for consistency with the ARM definition. Build tested on amd64 and i386 builds. Runtime tested on ARM. Signed-off-by: Ian Campbell <[email protected]> Cc: Stefano Stabellini <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: Boris Ostrovsky <[email protected]> Signed-off-by: David Vrabel <[email protected]>
* xen-pciback: notify hypervisor about devices intended to be assigned to guestsJan Beulich2013-03-221-2/+2
| | | | | | | | | | | | | | | | For MSI-X capable devices the hypervisor wants to write protect the MSI-X table and PBA, yet it can't assume that resources have been assigned to their final values at device enumeration time. Thus have pciback do that notification, as having the device controlled by it is a prerequisite to assigning the device to guests anyway. This is the kernel part of hypervisor side commit 4245d33 ("x86/MSI: add mechanism to fully protect MSI-X table from PV guest accesses") on the master branch of git://xenbits.xen.org/xen.git. CC: [email protected] Signed-off-by: Jan Beulich <[email protected]> Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
* xen/hypercall: fix hypercall fallback code for very old hypervisorsJan Beulich2012-11-041-14/+7
| | | | | | | | | | | | | | | | | | | | | | | While copying the argument structures in HYPERVISOR_event_channel_op() and HYPERVISOR_physdev_op() into the local variable is sufficiently safe even if the actual structure is smaller than the container one, copying back eventual output values the same way isn't: This may collide with on-stack variables (particularly "rc") which may change between the first and second memcpy() (i.e. the second memcpy() could discard that change). Move the fallback code into out-of-line functions, and handle all of the operations known by this old a hypervisor individually: Some don't require copying back anything at all, and for the rest use the individual argument structures' sizes rather than the container's. Reported-by: Dan Carpenter <[email protected]> Signed-off-by: Jan Beulich <[email protected]> [v2: Reduce #define/#undef usage in HYPERVISOR_physdev_op_compat().] [v3: Fix compile errors when modules use said hypercalls] [v4: Add xen_ prefix to the HYPERCALL_..] [v5: Alter the name and only EXPORT_SYMBOL_GPL one of them] Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
* xen/mce: Add mcelog support for Xen platformLiu, Jinsong2012-07-191-0/+8
| | | | | | | | | | | | | | | | | | | | | When MCA error occurs, it would be handled by Xen hypervisor first, and then the error information would be sent to initial domain for logging. This patch gets error information from Xen hypervisor and convert Xen format error into Linux format mcelog. This logic is basically self-contained, not touching other kernel components. By using tools like mcelog tool users could read specific error information, like what they did under native Linux. To test follow directions outlined in Documentation/acpi/apei/einj.txt Acked-and-tested-by: Borislav Petkov <[email protected]> Signed-off-by: Ke, Liping <[email protected]> Signed-off-by: Jiang, Yunhong <[email protected]> Signed-off-by: Jeremy Fitzhardinge <[email protected]> Signed-off-by: Liu, Jinsong <[email protected]> Signed-off-by: Konrad Rzeszutek Wilk <[email protected]>
* Merge branch 'upstream/xen-settime' of ↵Linus Torvalds2011-11-071-0/+8
|\ | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen * 'upstream/xen-settime' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: xen/dom0: set wallclock time in Xen xen: add dom0_op hypercall xen/acpi: Domain0 acpi parser related platform hypercall
| * xen: add dom0_op hypercallJeremy Fitzhardinge2011-09-261-0/+8
| | | | | | | | Signed-off-by: Jeremy Fitzhardinge <[email protected]>
* | xen/trace: add multicall tracingJeremy Fitzhardinge2011-07-181-0/+22
|/ | | | Signed-off-by: Jeremy Fitzhardinge <[email protected]>
* xen: cleancache shim to Xen Transcendent MemoryDan Magenheimer2011-05-261-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch provides a shim between the kernel-internal cleancache API (see Documentation/mm/cleancache.txt) and the Xen Transcendent Memory ABI (see http://oss.oracle.com/projects/tmem). Xen tmem provides "hypervisor RAM" as an ephemeral page-oriented pseudo-RAM store for cleancache pages, shared cleancache pages, and frontswap pages. Tmem provides enterprise-quality concurrency, full save/restore and live migration support, compression and deduplication. A presentation showing up to 8% faster performance and up to 52% reduction in sectors read on a kernel compile workload, despite aggressive in-kernel page reclamation ("self-ballooning") can be found at: http://oss.oracle.com/projects/tmem/dist/documentation/presentations/TranscendentMemoryXenSummit2010.pdf Signed-off-by: Dan Magenheimer <[email protected]> Reviewed-by: Jeremy Fitzhardinge <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Nick Piggin <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Rik Van Riel <[email protected]> Cc: Jan Beulich <[email protected]> Cc: Chris Mason <[email protected]> Cc: Andreas Dilger <[email protected]> Cc: Ted Ts'o <[email protected]> Cc: Mark Fasheh <[email protected]> Cc: Joel Becker <[email protected]> Cc: Nitin Gupta <[email protected]>
* xen: switch to new schedop hypercall by default.Ian Campbell2011-02-251-2/+2
| | | | | | | | Rename old interface to sched_op_compat and rename sched_op_new to simply sched_op. Signed-off-by: Ian Campbell <[email protected]> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
* xen: use new schedop interface for suspendIan Campbell2011-02-251-3/+10
| | | | | | | | Take the opportunity to comment on the semantics of the PV guest suspend hypercall arguments. Signed-off-by: Ian Campbell <[email protected]> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
* xen: add variable hypercall callerJeremy Fitzhardinge2010-10-201-0/+17
| | | | | | | | Allow non-constant hypercall to be called, for privcmd. [ Impact: make arbitrary hypercalls; needed for privcmd ] Signed-off-by: Jeremy Fitzhardinge <[email protected]>
* xen: Add support for HVM hypercalls.Jeremy Fitzhardinge2010-07-221-0/+6
| | | | | | Signed-off-by: Jeremy Fitzhardinge <[email protected]> Signed-off-by: Sheng Yang <[email protected]> Signed-off-by: Stefano Stabellini <[email protected]>
* x86: fix HYPERVISOR_update_descriptor()Jan Beulich2009-03-121-0/+2
| | | | | | | | | | | | Impact: fix potential oops during app-initiated LDT manipulation The underlying hypercall has differing argument requirements on 32- and 64-bit. Signed-off-by: Jan Beulich <[email protected]> Acked-by: Jeremy Fitzhardinge <[email protected]> LKML-Reference: <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
* xen: clean up asm/xen/hypervisor.hJeremy Fitzhardinge2008-12-161-0/+6
| | | | | | | | | | | Impact: cleanup hypervisor.h had accumulated a lot of crud, including lots of spurious #includes. Clean it all up, and go around fixing up everything else accordingly. Signed-off-by: Jeremy Fitzhardinge <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
* x86: drop double underscores from header guardsH. Peter Anvin2008-10-231-3/+3
| | | | | | | Drop double underscores from header guards in arch/x86/include. They are used inconsistently, and are not necessary. Signed-off-by: H. Peter Anvin <[email protected]>
* x86: Fix ASM_X86__ header guardsH. Peter Anvin2008-10-231-3/+3
| | | | | | | | | Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <[email protected]>
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