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authorsaturneric <[email protected]>2025-11-16 14:34:50 +0000
committersaturneric <[email protected]>2025-11-16 14:34:50 +0000
commit690862a8d74fee1e07f33dad44b761753f101779 (patch)
treef81bdcab8cd5a640518dba5056de6c62bd071eaf /tools/lib/bpf/usdt.c
parentMerge tag 'v6.17.7' into linux-6.17.y (diff)
parentLinux 6.17.8 (diff)
downloadkernel-linux-6.17.y.tar.gz
kernel-linux-6.17.y.zip
Merge tag 'v6.17.8' into linux-6.17.ylinux-6.17.y
This is the 6.17.8 stable release
Diffstat (limited to 'tools/lib/bpf/usdt.c')
-rw-r--r--tools/lib/bpf/usdt.c62
1 files changed, 57 insertions, 5 deletions
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 3373b9d45ac4..867bff6b0699 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -200,12 +200,23 @@ enum usdt_arg_type {
USDT_ARG_CONST,
USDT_ARG_REG,
USDT_ARG_REG_DEREF,
+ USDT_ARG_SIB,
};
/* should match exactly struct __bpf_usdt_arg_spec from usdt.bpf.h */
struct usdt_arg_spec {
__u64 val_off;
- enum usdt_arg_type arg_type;
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+ enum usdt_arg_type arg_type: 8;
+ __u16 idx_reg_off: 12;
+ __u16 scale_bitshift: 4;
+ __u8 __reserved: 8; /* keep reg_off offset stable */
+#else
+ __u8 __reserved: 8; /* keep reg_off offset stable */
+ __u16 idx_reg_off: 12;
+ __u16 scale_bitshift: 4;
+ enum usdt_arg_type arg_type: 8;
+#endif
short reg_off;
bool arg_signed;
char arg_bitshift;
@@ -1283,11 +1294,51 @@ static int calc_pt_regs_off(const char *reg_name)
static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)
{
- char reg_name[16];
- int len, reg_off;
- long off;
+ char reg_name[16] = {0}, idx_reg_name[16] = {0};
+ int len, reg_off, idx_reg_off, scale = 1;
+ long off = 0;
+
+ if (sscanf(arg_str, " %d @ %ld ( %%%15[^,] , %%%15[^,] , %d ) %n",
+ arg_sz, &off, reg_name, idx_reg_name, &scale, &len) == 5 ||
+ sscanf(arg_str, " %d @ ( %%%15[^,] , %%%15[^,] , %d ) %n",
+ arg_sz, reg_name, idx_reg_name, &scale, &len) == 4 ||
+ sscanf(arg_str, " %d @ %ld ( %%%15[^,] , %%%15[^)] ) %n",
+ arg_sz, &off, reg_name, idx_reg_name, &len) == 4 ||
+ sscanf(arg_str, " %d @ ( %%%15[^,] , %%%15[^)] ) %n",
+ arg_sz, reg_name, idx_reg_name, &len) == 3
+ ) {
+ /*
+ * Scale Index Base case:
+ * 1@-96(%rbp,%rax,8)
+ * 1@(%rbp,%rax,8)
+ * 1@-96(%rbp,%rax)
+ * 1@(%rbp,%rax)
+ */
+ arg->arg_type = USDT_ARG_SIB;
+ arg->val_off = off;
- if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n", arg_sz, &off, reg_name, &len) == 3) {
+ reg_off = calc_pt_regs_off(reg_name);
+ if (reg_off < 0)
+ return reg_off;
+ arg->reg_off = reg_off;
+
+ idx_reg_off = calc_pt_regs_off(idx_reg_name);
+ if (idx_reg_off < 0)
+ return idx_reg_off;
+ arg->idx_reg_off = idx_reg_off;
+
+ /* validate scale factor and set fields directly */
+ switch (scale) {
+ case 1: arg->scale_bitshift = 0; break;
+ case 2: arg->scale_bitshift = 1; break;
+ case 4: arg->scale_bitshift = 2; break;
+ case 8: arg->scale_bitshift = 3; break;
+ default:
+ pr_warn("usdt: invalid SIB scale %d, expected 1, 2, 4, 8\n", scale);
+ return -EINVAL;
+ }
+ } else if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n",
+ arg_sz, &off, reg_name, &len) == 3) {
/* Memory dereference case, e.g., -4@-20(%rbp) */
arg->arg_type = USDT_ARG_REG_DEREF;
arg->val_off = off;
@@ -1306,6 +1357,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
} else if (sscanf(arg_str, " %d @ %%%15s %n", arg_sz, reg_name, &len) == 2) {
/* Register read case, e.g., -4@%eax */
arg->arg_type = USDT_ARG_REG;
+ /* register read has no memory offset */
arg->val_off = 0;
reg_off = calc_pt_regs_off(reg_name);