system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-07-21 10:41:44 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

x86/kexec: Fix bug with call depth tracking

Browse source 
The call to cc_platform_has() triggers a fault and system crash if call depth
tracking is active because the GS segment has been reset by load_segments() and
GS_BASE is now 0 but call depth tracking uses per-CPU variables to operate.

Call cc_platform_has() earlier in the function when GS is still valid.

  [ bp: Massage. ]

Fixes: 5d8213864a ("x86/retbleed: Add SKL return thunk")
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20240603083036.637-1-bp@kernel.org
This commit is contained in:
David Kaplan 2024-06-02 13:19:09 -05:00 committed by Borislav Petkov (AMD)
parent c3f38fa61a
commit 93c1800b37
1 changed files with 9 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
arch/x86/kernel/machine_kexec_64.c
View file

@ -295,8 +295,15 @@ void machine_kexec_cleanup(struct kimage *image)
void machine_kexec(struct kimage *image)
{
unsigned long page_list[PAGES_NR];
void *control_page;
unsigned int host_mem_enc_active;
int save_ftrace_enabled;
void *control_page;
/*
* This must be done before load_segments() since if call depth tracking
* is used then GS must be valid to make any function calls.
*/
host_mem_enc_active = cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT);
#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)
@ -358,7 +365,7 @@ void machine_kexec(struct kimage *image)
(unsigned long)page_list,
image->start,
image->preserve_context,
cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT));
host_mem_enc_active);
#ifdef CONFIG_KEXEC_JUMP
if (image->preserve_context)