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authorPeter Zijlstra <peterz@infradead.org>2022-09-15 13:11:37 +0200
committerPeter Zijlstra <peterz@infradead.org>2022-10-17 16:41:19 +0200
commitee3e2469b3463d28ca4cde20e0283319ac6a562d (patch)
tree958265de2b1865d821630bc175df913052ac7f25 /samples/ftrace
parentx86/ftrace: Rebalance RSB (diff)
downloadlinux-ee3e2469b3463d28ca4cde20e0283319ac6a562d.tar.xz
linux-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')
-rw-r--r--samples/ftrace/ftrace-direct-modify.c3
-rw-r--r--samples/ftrace/ftrace-direct-multi-modify.c3
-rw-r--r--samples/ftrace/ftrace-direct-multi.c2
-rw-r--r--samples/ftrace/ftrace-direct-too.c2
-rw-r--r--samples/ftrace/ftrace-direct.c2
5 files changed, 12 insertions, 0 deletions
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index 39146fa83e20..de5a0f67f320 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -3,6 +3,7 @@
#include <linux/kthread.h>
#include <linux/ftrace.h>
#include <asm/asm-offsets.h>
+#include <asm/nospec-branch.h>
extern void my_direct_func1(void);
extern void my_direct_func2(void);
@@ -34,6 +35,7 @@ asm (
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
" call my_direct_func1\n"
" leave\n"
" .size my_tramp1, .-my_tramp1\n"
@@ -45,6 +47,7 @@ asm (
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
" call my_direct_func2\n"
" leave\n"
ASM_RET
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index 65aa94d96f4e..d52370cad0b6 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -3,6 +3,7 @@
#include <linux/kthread.h>
#include <linux/ftrace.h>
#include <asm/asm-offsets.h>
+#include <asm/nospec-branch.h>
extern void my_direct_func1(unsigned long ip);
extern void my_direct_func2(unsigned long ip);
@@ -32,6 +33,7 @@ asm (
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
" pushq %rdi\n"
" movq 8(%rbp), %rdi\n"
" call my_direct_func1\n"
@@ -46,6 +48,7 @@ asm (
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
" pushq %rdi\n"
" movq 8(%rbp), %rdi\n"
" call my_direct_func2\n"
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index 41ded7c615c7..ec1088922517 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -5,6 +5,7 @@
#include <linux/ftrace.h>
#include <linux/sched/stat.h>
#include <asm/asm-offsets.h>
+#include <asm/nospec-branch.h>
extern void my_direct_func(unsigned long ip);
@@ -27,6 +28,7 @@ asm (
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
" pushq %rdi\n"
" movq 8(%rbp), %rdi\n"
" call my_direct_func\n"
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 6690468c5cc2..e13fb59a2b47 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -4,6 +4,7 @@
#include <linux/mm.h> /* for handle_mm_fault() */
#include <linux/ftrace.h>
#include <asm/asm-offsets.h>
+#include <asm/nospec-branch.h>
extern void my_direct_func(struct vm_area_struct *vma,
unsigned long address, unsigned int flags);
@@ -29,6 +30,7 @@ asm (
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
+ CALL_DEPTH_ACCOUNT
" pushq %rdi\n"
" pushq %rsi\n"
" pushq %rdx\n"
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"