[PATCH-4.19-stable 2/2] x86/stackframe, x86/ftrace: Add pt_regs frame annotations

[Dmitry Safonov]

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

[ Upstream commit ea1ed38dba64b64a245ab8ca1406269d17b99485 ]

When CONFIG_FRAME_POINTER, we should mark pt_regs frames.

Fixes user-visible warning for unwinder (i.e, ftrace's stack tracer):
> WARNING: kernel stack frame pointer at 00000000bceb5183 in Coronavirus:3282 has bad value           (null)
>  unwind stack type:0 next_sp:          (null) mask:0x2 graph_idx:0
>  000000009630aa47: ffffc9000126fdb0 (0xffffc9000126fdb0)
>  0000000020360f53: ffffffff81038e33 (__save_stack_trace+0xcb/0xee)
>  00000000675081f2: 0000000000000000 ...
>  0000000043198fe7: ffffc9000126c000 (0xffffc9000126c000)
>  0000000008a46231: ffffc90001270000 (0xffffc90001270000)
[..]

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
[4.19 backport; added user-visible changelog]
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
---
 arch/x86/kernel/ftrace_32.S | 3 +++
 arch/x86/kernel/ftrace_64.S | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index 4c8440de3355..83f18e829ac7 100644
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -9,6 +9,7 @@
 #include <asm/export.h>
 #include <asm/ftrace.h>
 #include <asm/nospec-branch.h>
+#include <asm/frame.h>
 
 #ifdef CC_USING_FENTRY
 # define function_hook	__fentry__
@@ -131,6 +132,8 @@ ENTRY(ftrace_regs_caller)
 	pushl	%ecx
 	pushl	%ebx
 
+	ENCODE_FRAME_POINTER
+
 	movl	12*4(%esp), %eax		/* Load ip (1st parameter) */
 	subl	$MCOUNT_INSN_SIZE, %eax		/* Adjust ip */
 #ifdef CC_USING_FENTRY
diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index 75f2b36b41a6..24b9abf718e8 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -9,6 +9,7 @@
 #include <asm/export.h>
 #include <asm/nospec-branch.h>
 #include <asm/unwind_hints.h>
+#include <asm/frame.h>
 
 	.code64
 	.section .entry.text, "ax"
@@ -222,6 +223,8 @@ GLOBAL(ftrace_regs_caller_op_ptr)
 	leaq MCOUNT_REG_SIZE+8*2(%rsp), %rcx
 	movq %rcx, RSP(%rsp)
 
+	ENCODE_FRAME_POINTER
+
 	/* regs go into 4th parameter */
 	leaq (%rsp), %rcx
 
-- 
2.25.0