From c416b5bac6ad6ffe21e36225553b82ff2ec1558c Mon Sep 17 00:00:00 2001
From: "Xin Li (Intel)" <xin@zytor.com>
Date: Mon, 4 Mar 2024 00:33:33 -0800
Subject: x86/fred: Fix init_task thread stack pointer initialization
As TOP_OF_KERNEL_STACK_PADDING was defined as 0 on x86_64, it went
unnoticed that the initialization of the .sp field in INIT_THREAD and some
calculations in the low level startup code do not take the padding into
account.
FRED enabled kernels require a 16 byte padding, which means that the init
task initialization and the low level startup code use the wrong stack
offset.
Subtract TOP_OF_KERNEL_STACK_PADDING in all affected places to adjust for
this.
Fixes: 65c9cc9e2c14 ("x86/fred: Reserve space for the FRED stack frame")
Fixes: 3adee777ad0d ("x86/smpboot: Remove initial_stack on 64-bit")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Closes: https://lore.kernel.org/oe-lkp/202402262159.183c2a37-lkp@intel.com
Link: https://lore.kernel.org/r/20240304083333.449322-1-xin@zytor.com
---
arch/x86/include/asm/processor.h | 6 ++++--
arch/x86/kernel/head_64.S | 3 ++-
arch/x86/xen/xen-head.S | 2 +-
3 files changed, 7 insertions(+), 4 deletions(-)
(limited to 'arch')
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 26620d7642a9..17fe81998ce4 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -664,8 +664,10 @@ static __always_inline void prefetchw(const void *x)
#else
extern unsigned long __end_init_task[];
-#define INIT_THREAD { \
- .sp = (unsigned long)&__end_init_task - sizeof(struct pt_regs), \
+#define INIT_THREAD { \
+ .sp = (unsigned long)&__end_init_task - \
+ TOP_OF_KERNEL_STACK_PADDING - \
+ sizeof(struct pt_regs), \
}
extern unsigned long KSTK_ESP(struct task_struct *task);
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index d4918d03efb4..c38e43589046 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -26,6 +26,7 @@
#include <asm/apicdef.h>
#include <asm/fixmap.h>
#include <asm/smp.h>
+#include <asm/thread_info.h>
/*
* We are not able to switch in one step to the final KERNEL ADDRESS SPACE
@@ -66,7 +67,7 @@ SYM_CODE_START_NOALIGN(startup_64)
mov %rsi, %r15
/* Set up the stack for verify_cpu() */
- leaq (__end_init_task - PTREGS_SIZE)(%rip), %rsp
+ leaq (__end_init_task - TOP_OF_KERNEL_STACK_PADDING - PTREGS_SIZE)(%rip), %rsp
leaq _text(%rip), %rdi
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index a0ea285878db..04101b984f24 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -49,7 +49,7 @@ SYM_CODE_START(startup_xen)
ANNOTATE_NOENDBR
cld
- leaq (__end_init_task - PTREGS_SIZE)(%rip), %rsp
+ leaq (__end_init_task - TOP_OF_KERNEL_STACK_PADDING - PTREGS_SIZE)(%rip), %rsp
/* Set up %gs.
*
--
cgit v1.2.3-70-g09d2