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Commit 3b0c0622 authored by Will Deacon's avatar Will Deacon Committed by Russell King
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ARM: 7442/1: Revert "remove unused restart trampoline" 



This reverts commit fa18484d.

We need the restart trampoline back so that we can revert a related
problematic patch 6b5c8045 ("arm: new
way of handling ERESTART_RESTARTBLOCK").

Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 82401bf1

arch/arm/kernel/signal.c

+13 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
 */

#define SWI_SYS_SIGRETURN	(0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))

#define SWI_SYS_RT_SIGRETURN	(0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))

#define SWI_SYS_RESTART		(0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)



/*

 * With EABI, the syscall number has to be loaded into r7.
@@ -46,6 +47,18 @@ const unsigned long sigreturn_codes[7] = { 
	MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,

};



/*

 * Either we support OABI only, or we have EABI with the OABI

 * compat layer enabled.  In the later case we don't know if

 * user space is EABI or not, and if not we must not clobber r7.

 * Always using the OABI syscall solves that issue and works for

 * all those cases.

 */

const unsigned long syscall_restart_code[2] = {

	SWI_SYS_RESTART,	/* swi	__NR_restart_syscall */

	0xe49df004,		/* ldr	pc, [sp], #4 */

};



/*

 * atomically swap in the new signal mask, and wait for a signal.

 */

arch/arm/kernel/signal.h

+2 −0
Original line number Diff line number Diff line
@@ -8,5 +8,7 @@ 
 * published by the Free Software Foundation.

 */

#define KERN_SIGRETURN_CODE	(CONFIG_VECTORS_BASE + 0x00000500)

#define KERN_RESTART_CODE	(KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))



extern const unsigned long sigreturn_codes[7];

extern const unsigned long syscall_restart_code[2];

arch/arm/kernel/traps.c

+2 −0
Original line number Diff line number Diff line
@@ -820,6 +820,8 @@ void __init early_trap_init(void *vectors_base) 
	 */

	memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),

	       sigreturn_codes, sizeof(sigreturn_codes));

	memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),

	       syscall_restart_code, sizeof(syscall_restart_code));



	flush_icache_range(vectors, vectors + PAGE_SIZE);

	modify_domain(DOMAIN_USER, DOMAIN_CLIENT);