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arm64: fix el2_setup check of CurrentEL

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The CurrentEL system register reports the Current Exception Level
of the CPU. It doesn't say anything about the stack handling, and
yet we compare it to PSR_MODE_EL2t and PSR_MODE_EL2h.

It works by chance because PSR_MODE_EL2t happens to match the right
bits, but that's otherwise a very bad idea. Just check for the EL
value instead.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[catalin.marinas@arm.com: fixed arch/arm64/kernel/efi-entry.S]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Marc Zyngier 2014-06-06 14:16:21 +01:00 committed by Catalin Marinas
parent 923b8f5044
commit 974c8e450b
3 changed files with 6 additions and 4 deletions
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4
arch/arm64/include/asm/ptrace.h
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@ -21,6 +21,10 @@
#include <uapi/asm/ptrace.h>
/* Current Exception Level values, as contained in CurrentEL */
#define CurrentEL_EL1 (1 << 2)
#define CurrentEL_EL2 (2 << 2)
/* AArch32-specific ptrace requests */
#define COMPAT_PTRACE_GETREGS 12
#define COMPAT_PTRACE_SETREGS 13

3
arch/arm64/kernel/efi-entry.S
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@ -78,8 +78,7 @@ ENTRY(efi_stub_entry)
/* Turn off Dcache and MMU */
mrs x0, CurrentEL
cmp x0, #PSR_MODE_EL2t
ccmp x0, #PSR_MODE_EL2h, #0x4, ne
cmp x0, #CurrentEL_EL2
b.ne 1f
mrs x0, sctlr_el2
bic x0, x0, #1 << 0 // clear SCTLR.M

3
arch/arm64/kernel/head.S
View File

@ -270,8 +270,7 @@ ENDPROC(stext)
*/
ENTRY(el2_setup)
mrs x0, CurrentEL
cmp x0, #PSR_MODE_EL2t
ccmp x0, #PSR_MODE_EL2h, #0x4, ne
cmp x0, #CurrentEL_EL2
b.ne 1f
mrs x0, sctlr_el2
CPU_BE( orr x0, x0, #(1 << 25) ) // Set the EE bit for EL2