This is a note to let you know that I've just added the patch titled
xtensa: fix MAKE_PC_FROM_RA second argument
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xtensa-fix-make_pc_from_ra-second-argument.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0e60f0b75884677fb9f4f2ad40d52b43451564d5 Mon Sep 17 00:00:00 2001
From: Max Filippov <jcmvbkbc@xxxxxxxxx>
Date: Sat, 17 Feb 2024 05:15:42 -0800
Subject: xtensa: fix MAKE_PC_FROM_RA second argument
From: Max Filippov <jcmvbkbc@xxxxxxxxx>
commit 0e60f0b75884677fb9f4f2ad40d52b43451564d5 upstream.
Xtensa has two-argument MAKE_PC_FROM_RA macro to convert a0 to an actual
return address because when windowed ABI is used call{,x}{4,8,12}
opcodes stuff encoded window size into the top 2 bits of the register
that becomes a return address in the called function. Second argument of
that macro is supposed to be an address having these 2 topmost bits set
correctly, but the comment suggested that that could be the stack
address. However the stack doesn't have to be in the same 1GByte region
as the code, especially in noMMU XIP configurations.
Fix the comment and use either _text or regs->pc as the second argument
for the MAKE_PC_FROM_RA macro.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/xtensa/include/asm/processor.h | 8 ++++----
arch/xtensa/include/asm/ptrace.h | 2 +-
arch/xtensa/kernel/process.c | 5 +++--
arch/xtensa/kernel/stacktrace.c | 3 ++-
4 files changed, 10 insertions(+), 8 deletions(-)
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -115,9 +115,9 @@
#define MAKE_RA_FOR_CALL(ra,ws) (((ra) & 0x3fffffff) | (ws) << 30)
/* Convert return address to a valid pc
- * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
+ * Note: 'text' is the address within the same 1GB range as the ra
*/
-#define MAKE_PC_FROM_RA(ra,sp) (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
+#define MAKE_PC_FROM_RA(ra, text) (((ra) & 0x3fffffff) | ((unsigned long)(text) & 0xc0000000))
#elif defined(__XTENSA_CALL0_ABI__)
@@ -127,9 +127,9 @@
#define MAKE_RA_FOR_CALL(ra, ws) (ra)
/* Convert return address to a valid pc
- * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
+ * Note: 'text' is not used as 'ra' is always the full address
*/
-#define MAKE_PC_FROM_RA(ra, sp) (ra)
+#define MAKE_PC_FROM_RA(ra, text) (ra)
#else
#error Unsupported Xtensa ABI
--- a/arch/xtensa/include/asm/ptrace.h
+++ b/arch/xtensa/include/asm/ptrace.h
@@ -87,7 +87,7 @@ struct pt_regs {
# define user_mode(regs) (((regs)->ps & 0x00000020)!=0)
# define instruction_pointer(regs) ((regs)->pc)
# define return_pointer(regs) (MAKE_PC_FROM_RA((regs)->areg[0], \
- (regs)->areg[1]))
+ (regs)->pc))
# ifndef CONFIG_SMP
# define profile_pc(regs) instruction_pointer(regs)
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -47,6 +47,7 @@
#include <asm/asm-offsets.h>
#include <asm/regs.h>
#include <asm/hw_breakpoint.h>
+#include <asm/sections.h>
#include <asm/traps.h>
extern void ret_from_fork(void);
@@ -380,7 +381,7 @@ unsigned long __get_wchan(struct task_st
int count = 0;
sp = p->thread.sp;
- pc = MAKE_PC_FROM_RA(p->thread.ra, p->thread.sp);
+ pc = MAKE_PC_FROM_RA(p->thread.ra, _text);
do {
if (sp < stack_page + sizeof(struct task_struct) ||
@@ -392,7 +393,7 @@ unsigned long __get_wchan(struct task_st
/* Stack layout: sp-4: ra, sp-3: sp' */
- pc = MAKE_PC_FROM_RA(SPILL_SLOT(sp, 0), sp);
+ pc = MAKE_PC_FROM_RA(SPILL_SLOT(sp, 0), _text);
sp = SPILL_SLOT(sp, 1);
} while (count++ < 16);
return 0;
--- a/arch/xtensa/kernel/stacktrace.c
+++ b/arch/xtensa/kernel/stacktrace.c
@@ -13,6 +13,7 @@
#include <linux/stacktrace.h>
#include <asm/ftrace.h>
+#include <asm/sections.h>
#include <asm/stacktrace.h>
#include <asm/traps.h>
#include <linux/uaccess.h>
@@ -189,7 +190,7 @@ void walk_stackframe(unsigned long *sp,
if (a1 <= (unsigned long)sp)
break;
- frame.pc = MAKE_PC_FROM_RA(a0, a1);
+ frame.pc = MAKE_PC_FROM_RA(a0, _text);
frame.sp = a1;
if (fn(&frame, data))
Patches currently in stable-queue which might be from jcmvbkbc@xxxxxxxxx are
queue-6.8/xtensa-fix-make_pc_from_ra-second-argument.patch
