From e00d349e7781a92cf35b242259c9e5341a9661bb Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 22 Jun 2005 20:26:05 +0100 Subject: [PATCH] [PATCH] ARM: Move signal return code into vector page Move the signal return code into the vector page instead of placing it on the user mode stack, which will allow us to avoid flushing the instruction cache on signals, as well as eventually allowing non-exec stack. Signed-off-by: Russell King --- arch/arm/kernel/signal.c | 29 +++++++++++++++++++---------- arch/arm/kernel/signal.h | 12 ++++++++++++ arch/arm/kernel/traps.c | 9 +++++++++ 3 files changed, 40 insertions(+), 10 deletions(-) create mode 100644 arch/arm/kernel/signal.h diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 931919fd51..07ddeed617 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -19,6 +19,7 @@ #include #include "ptrace.h" +#include "signal.h" #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) @@ -35,7 +36,7 @@ #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) -static const unsigned long retcodes[4] = { +const unsigned long sigreturn_codes[4] = { SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN }; @@ -500,17 +501,25 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka, if (ka->sa.sa_flags & SA_SIGINFO) idx += 2; - if (__put_user(retcodes[idx], rc)) + if (__put_user(sigreturn_codes[idx], rc)) return 1; - /* - * Ensure that the instruction cache sees - * the return code written onto the stack. - */ - flush_icache_range((unsigned long)rc, - (unsigned long)(rc + 1)); - - retcode = ((unsigned long)rc) + thumb; + if (cpsr & MODE32_BIT) { + /* + * 32-bit code can use the new high-page + * signal return code support. + */ + retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; + } else { + /* + * Ensure that the instruction cache sees + * the return code written onto the stack. + */ + flush_icache_range((unsigned long)rc, + (unsigned long)(rc + 1)); + + retcode = ((unsigned long)rc) + thumb; + } } regs->ARM_r0 = usig; diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h new file mode 100644 index 0000000000..91d26faca6 --- /dev/null +++ b/arch/arm/kernel/signal.h @@ -0,0 +1,12 @@ +/* + * linux/arch/arm/kernel/signal.h + * + * Copyright (C) 2005 Russell King. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#define KERN_SIGRETURN_CODE 0xffff0500 + +extern const unsigned long sigreturn_codes[4]; diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 45d2a032d8..2fb0a4cfb3 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -30,6 +30,7 @@ #include #include "ptrace.h" +#include "signal.h" const char *processor_modes[]= { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , @@ -683,6 +684,14 @@ void __init trap_init(void) memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start); memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start); memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz); + + /* + * Copy signal return handlers into the vector page, and + * set sigreturn to be a pointer to these. + */ + memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes, + sizeof(sigreturn_codes)); + flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE); modify_domain(DOMAIN_USER, DOMAIN_CLIENT); } -- 2.39.5