Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2025-01-10 07:00:48 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

arm64: fix hyp mode mismatch detection

Browse Source 
Commit 828e9834e9a5b7e6 ("arm64: head: create a new function for setting
the boot_cpu_mode flag") added BOOT_CPU_MODE_EL1, a nonzero value
replacing uses of zero. However it failed to update __boot_cpu_mode
appropriately.

A CPU booted at EL2 writes BOOT_CPU_MODE_EL2 to __boot_cpu_mode[0], and
a CPU booted at EL1 writes BOOT_CPU_MODE_EL1 to __boot_cpu_mode[1].
Later is_hyp_mode_mismatched() determines there to be a mismatch if
__boot_cpu_mode[0] != __boot_cpu_mode[1].

If all CPUs are booted at EL1, __boot_cpu_mode[0] will be set to
BOOT_CPU_MODE_EL1, but __boot_cpu_mode[1] will retain its initial value
of zero, and is_hyp_mode_mismatched will erroneously determine that the
boot modes are mismatched. This hasn't been a problem so far, but later
patches which will make use of is_hyp_mode_mismatched() expect it to
work correctly.

This patch initialises __boot_cpu_mode[1] to BOOT_CPU_MODE_EL1, fixing
the erroneous mismatch detection when all CPUs are booted at EL1.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Mark Rutland 2015-03-13 16:14:36 +00:00 committed by Will Deacon
parent 137650aad9
commit 424a383824
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/kernel/head.S
View File

@ -588,7 +588,7 @@ ENDPROC(set_cpu_boot_mode_flag)
.align L1_CACHE_SHIFT .align L1_CACHE_SHIFT
ENTRY(__boot_cpu_mode) ENTRY(__boot_cpu_mode)
.long BOOT_CPU_MODE_EL2 .long BOOT_CPU_MODE_EL2
.long 0 .long BOOT_CPU_MODE_EL1
.popsection .popsection
#ifdef CONFIG_SMP #ifdef CONFIG_SMP