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Commit 974c8e45 authored by Marc Zyngier's avatar Marc Zyngier Committed by Catalin Marinas
Browse files

arm64: fix el2_setup check of CurrentEL 



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: default avatarMarc Zyngier <marc.zyngier@arm.com>
[catalin.marinas@arm.com: fixed arch/arm64/kernel/efi-entry.S]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 923b8f50

arch/arm64/include/asm/ptrace.h

+4 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/kernel/efi-entry.S

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

arch/arm64/kernel/head.S

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