Commit c416b5ba authored by Xin Li (Intel)'s avatar Xin Li (Intel) Committed by Thomas Gleixner
Browse files

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: 65c9cc9e ("x86/fred: Reserve space for the FRED stack frame")
Fixes: 3adee777 ("x86/smpboot: Remove initial_stack on 64-bit")
Reported-by: default avatarkernel test robot <oliver.sang@intel.com>
Signed-off-by: default avatarXin Li (Intel) <xin@zytor.com>
Signed-off-by: default avatarThomas 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
parent e1384190

arch/x86/include/asm/processor.h

+4 −2
Original line number Diff line number Diff line
@@ -665,7 +665,9 @@ static __always_inline void prefetchw(const void *x) 
extern unsigned long __end_init_task[];



#define INIT_THREAD {							\

	.sp	= (unsigned long)&__end_init_task - sizeof(struct pt_regs), \

	.sp	= (unsigned long)&__end_init_task -			\

		  TOP_OF_KERNEL_STACK_PADDING -				\

		  sizeof(struct pt_regs),				\

}



extern unsigned long KSTK_ESP(struct task_struct *task);

arch/x86/kernel/head_64.S

+2 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/xen/xen-head.S

+1 −1
Original line number Diff line number Diff line
@@ -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.

	 *