Commit e4f2006f authored by Helge Deller's avatar Helge Deller
Browse files

parisc: Reduce sigreturn trampoline to 3 instructions 



We can move the INSN_LDI_R20 instruction into the branch delay slot.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 3e4a1aff

arch/parisc/include/asm/rt_sigframe.h

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
#ifndef _ASM_PARISC_RT_SIGFRAME_H

#define _ASM_PARISC_RT_SIGFRAME_H



#define SIGRETURN_TRAMP 4

#define SIGRETURN_TRAMP 3

#define SIGRESTARTBLOCK_TRAMP 5 

#define TRAMP_SIZE (SIGRETURN_TRAMP + SIGRESTARTBLOCK_TRAMP)

arch/parisc/kernel/signal.c

+6 −7
Original line number Diff line number Diff line
@@ -288,22 +288,21 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs, 
	   already in userspace. The first words of tramp are used to

	   save the previous sigrestartblock trampoline that might be

	   on the stack. We start the sigreturn trampoline at 

	   SIGRESTARTBLOCK_TRAMP+X. */

	   SIGRESTARTBLOCK_TRAMP. */

	err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,

			&frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);

	err |= __put_user(INSN_LDI_R20, 

			&frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);

	err |= __put_user(INSN_BLE_SR2_R0, 

			&frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);

	err |= __put_user(INSN_LDI_R20,

			&frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);

	err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);



	start = (unsigned long) &frame->tramp[0];

	end = (unsigned long) &frame->tramp[TRAMP_SIZE];

	start = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP+0];

	end = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP+3];

	flush_user_dcache_range_asm(start, end);

	flush_user_icache_range_asm(start, end);



	/* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP

	 * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP

	 * TRAMP Words 5-7, Length 3 = SIGRETURN_TRAMP

	 * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP

	 */

	rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];

arch/parisc/kernel/signal32.h

+1 −1
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ struct compat_regfile { 
        compat_int_t rf_sar;

};



#define COMPAT_SIGRETURN_TRAMP 4

#define COMPAT_SIGRETURN_TRAMP 3

#define COMPAT_SIGRESTARTBLOCK_TRAMP 5

#define COMPAT_TRAMP_SIZE (COMPAT_SIGRETURN_TRAMP + \

				COMPAT_SIGRESTARTBLOCK_TRAMP)