diff options
Diffstat (limited to 'arch/x86/kernel/perf_regs.c')
-rw-r--r-- | arch/x86/kernel/perf_regs.c | 40 |
1 files changed, 10 insertions, 30 deletions
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c index 781861c..da8cb98 100644 --- a/arch/x86/kernel/perf_regs.c +++ b/arch/x86/kernel/perf_regs.c @@ -131,10 +131,11 @@ void perf_get_regs_user(struct perf_regs *regs_user, } /* - * RIP, flags, and the argument registers are usually saved. - * orig_ax is probably okay, too. + * These registers are always saved on 64-bit syscall entry. + * On 32-bit entry points, they are saved too except r8..r11. */ regs_user_copy->ip = user_regs->ip; + regs_user_copy->ax = user_regs->ax; regs_user_copy->cx = user_regs->cx; regs_user_copy->dx = user_regs->dx; regs_user_copy->si = user_regs->si; @@ -145,9 +146,12 @@ void perf_get_regs_user(struct perf_regs *regs_user, regs_user_copy->r11 = user_regs->r11; regs_user_copy->orig_ax = user_regs->orig_ax; regs_user_copy->flags = user_regs->flags; + regs_user_copy->sp = user_regs->sp; + regs_user_copy->cs = user_regs->cs; + regs_user_copy->ss = user_regs->ss; /* - * Don't even try to report the "rest" regs. + * Most system calls don't save these registers, don't report them. */ regs_user_copy->bx = -1; regs_user_copy->bp = -1; @@ -158,37 +162,13 @@ void perf_get_regs_user(struct perf_regs *regs_user, /* * For this to be at all useful, we need a reasonable guess for - * sp and the ABI. Be careful: we're in NMI context, and we're + * the ABI. Be careful: we're in NMI context, and we're * considering current to be the current task, so we should * be careful not to look at any other percpu variables that might * change during context switches. */ - if (IS_ENABLED(CONFIG_IA32_EMULATION) && - task_thread_info(current)->status & TS_COMPAT) { - /* Easy case: we're in a compat syscall. */ - regs_user->abi = PERF_SAMPLE_REGS_ABI_32; - regs_user_copy->sp = user_regs->sp; - regs_user_copy->cs = user_regs->cs; - regs_user_copy->ss = user_regs->ss; - } else if (user_regs->orig_ax != -1) { - /* - * We're probably in a 64-bit syscall. - * Warning: this code is severely racy. At least it's better - * than just blindly copying user_regs. - */ - regs_user->abi = PERF_SAMPLE_REGS_ABI_64; - regs_user_copy->sp = this_cpu_read(old_rsp); - regs_user_copy->cs = __USER_CS; - regs_user_copy->ss = __USER_DS; - regs_user_copy->cx = -1; /* usually contains garbage */ - } else { - /* We're probably in an interrupt or exception. */ - regs_user->abi = user_64bit_mode(user_regs) ? - PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; - regs_user_copy->sp = user_regs->sp; - regs_user_copy->cs = user_regs->cs; - regs_user_copy->ss = user_regs->ss; - } + regs_user->abi = user_64bit_mode(user_regs) ? + PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32; regs_user->regs = regs_user_copy; } |