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author | Peter Zijlstra <peterz@infradead.org> | 2022-09-15 13:11:37 +0200 |
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committer | Peter Zijlstra <peterz@infradead.org> | 2022-10-17 16:41:19 +0200 |
commit | ee3e2469b3463d28ca4cde20e0283319ac6a562d (patch) | |
tree | 958265de2b1865d821630bc175df913052ac7f25 /samples/ftrace/ftrace-direct.c | |
parent | 36b64f101219dd9e6e4f0ea880b64e8a90da547b (diff) | |
download | linux-stable-ee3e2469b3463d28ca4cde20e0283319ac6a562d.tar.gz linux-stable-ee3e2469b3463d28ca4cde20e0283319ac6a562d.tar.bz2 linux-stable-ee3e2469b3463d28ca4cde20e0283319ac6a562d.zip |
x86/ftrace: Make it call depth tracking aware
Since ftrace has trampolines, don't use thunks for the __fentry__ site
but instead require that every function called from there includes
accounting. This very much includes all the direct-call functions.
Additionally, ftrace uses ROP tricks in two places:
- return_to_handler(), and
- ftrace_regs_caller() when pt_regs->orig_ax is set by a direct-call.
return_to_handler() already uses a retpoline to replace an
indirect-jump to defeat IBT, since this is a jump-type retpoline, make
sure there is no accounting done and ALTERNATIVE the RET into a ret.
ftrace_regs_caller() does much the same and gets the same treatment.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111148.927545073@infradead.org
Diffstat (limited to 'samples/ftrace/ftrace-direct.c')
-rw-r--r-- | samples/ftrace/ftrace-direct.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c index e8f1e440b9b8..1f769d0db20f 100644 --- a/samples/ftrace/ftrace-direct.c +++ b/samples/ftrace/ftrace-direct.c @@ -4,6 +4,7 @@ #include <linux/sched.h> /* for wake_up_process() */ #include <linux/ftrace.h> #include <asm/asm-offsets.h> +#include <asm/nospec-branch.h> extern void my_direct_func(struct task_struct *p); @@ -26,6 +27,7 @@ asm ( ASM_ENDBR " pushq %rbp\n" " movq %rsp, %rbp\n" + CALL_DEPTH_ACCOUNT " pushq %rdi\n" " call my_direct_func\n" " popq %rdi\n" |