From 9973290ce20ace7cac8ad06f753468c0b826fd0f Mon Sep 17 00:00:00 2001 From: David Brown Date: Wed, 20 Jun 2012 22:52:24 +0100 Subject: ARM: 7428/1: Prevent KALLSYM size mismatch on ARM. ARM builds seem to be plagued by an occasional build error: Inconsistent kallsyms data This is a bug - please report about it Try "make KALLSYMS_EXTRA_PASS=1" as a workaround The problem has to do with alignment of some sections by the linker. The kallsyms data is built in two passes by first linking the kernel without it, and then linking the kernel again with the symbols included. Normally, this just shifts the symbols, without changing their order, and the compression used by the kallsyms gives the same result. On non SMP, the per CPU data is empty. Depending on the where the alignment ends up, it can come out as either: +-------------------+ | last text segment | +-------------------+ /* padding */ +-------------------+ <- L1_CACHE_BYTES alignemnt | per cpu (empty) | +-------------------+ __per_cpu_end: /* padding */ __data_loc: +-------------------+ <- THREAD_SIZE alignment | data | +-------------------+ or +-------------------+ | last text segment | +-------------------+ /* padding */ +-------------------+ <- L1_CACHE_BYTES alignemnt | per cpu (empty) | +-------------------+ __per_cpu_end: /* no padding */ __data_loc: +-------------------+ <- THREAD_SIZE alignment | data | +-------------------+ if the alignment satisfies both. Because symbols that have the same address are sorted by 'nm -n', the second case will be in a different order than the first case. This changes the compression, changing the size of the kallsym data, causing the build failure. The KALLSYMS_EXTRA_PASS=1 workaround usually works, but it is still possible to have the alignment change between the second and third pass. It's probably even possible for it to never reach a fixedpoint. The problem only occurs on non-SMP, when the per-cpu data is empty, and when the data segment has alignment (and immediately follows the text segments). Fix this by only including the per_cpu section on SMP, when it is not empty. Signed-off-by: David Brown Signed-off-by: Russell King --- arch/arm/kernel/vmlinux.lds.S | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index 43a31fb06318..36ff15bbfdd4 100644 --- a/arch/arm/kernel/vmlinux.lds.S +++ b/arch/arm/kernel/vmlinux.lds.S @@ -183,7 +183,9 @@ SECTIONS } #endif +#ifdef CONFIG_SMP PERCPU_SECTION(L1_CACHE_BYTES) +#endif #ifdef CONFIG_XIP_KERNEL __data_loc = ALIGN(4); /* location in binary */ -- cgit v1.2.3 From 3b0c06226783ffc836217eb34f7eca311b1e63f7 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 4 Jul 2012 18:16:30 +0100 Subject: ARM: 7442/1: Revert "remove unused restart trampoline" This reverts commit fa18484d0947b976a769d15c83c50617493c81c1. We need the restart trampoline back so that we can revert a related problematic patch 6b5c8045ecc7e726cdaa2a9d9c8e5008050e1252 ("arm: new way of handling ERESTART_RESTARTBLOCK"). Acked-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/signal.c | 13 +++++++++++++ arch/arm/kernel/signal.h | 2 ++ arch/arm/kernel/traps.c | 2 ++ 3 files changed, 17 insertions(+) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index fd2392a17ac1..6d3bce5bd7bc 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -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. */ diff --git a/arch/arm/kernel/signal.h b/arch/arm/kernel/signal.h index 5ff067b7c752..6fcfe8398aa4 100644 --- a/arch/arm/kernel/signal.h +++ b/arch/arm/kernel/signal.h @@ -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]; diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 4928d89758f4..3647170e9a16 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -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); -- cgit v1.2.3 From 433e2f307beff8adba241646ce9108544e0c5a03 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 4 Jul 2012 18:17:16 +0100 Subject: ARM: 7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK" This reverts commit 6b5c8045ecc7e726cdaa2a9d9c8e5008050e1252. Conflicts: arch/arm/kernel/ptrace.c The new syscall restarting code can lead to problems if we take an interrupt in userspace just before restarting the svc instruction. If a signal is delivered when returning from the interrupt, the TIF_SYSCALL_RESTARTSYS will remain set and cause any syscalls executed from the signal handler to be treated as a restart of the previously interrupted system call. This includes the final sigreturn call, meaning that we may fail to exit from the signal context. Furthermore, if a system call made from the signal handler requires a restart via the restart_block, it is possible to clear the thread flag and fail to restart the originally interrupted system call. The right solution to this problem is to perform the restarting in the kernel, avoiding the possibility of handling a further signal before the restart is complete. Since we're almost at -rc6, let's revert the new method for now and aim for in-kernel restarting at a later date. Acked-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/include/asm/thread_info.h | 5 +---- arch/arm/kernel/ptrace.c | 3 --- arch/arm/kernel/signal.c | 33 +++++++++++++++++++++++++++------ 3 files changed, 28 insertions(+), 13 deletions(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index b79f8e97f775..af7b0bda3355 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -148,7 +148,6 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *, #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ #define TIF_SYSCALL_TRACE 8 #define TIF_SYSCALL_AUDIT 9 -#define TIF_SYSCALL_RESTARTSYS 10 #define TIF_POLLING_NRFLAG 16 #define TIF_USING_IWMMXT 17 #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ @@ -164,11 +163,9 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *, #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) #define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) -#define _TIF_SYSCALL_RESTARTSYS (1 << TIF_SYSCALL_RESTARTSYS) /* Checks for any syscall work in entry-common.S */ -#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ - _TIF_SYSCALL_RESTARTSYS) +#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT) /* * Change these and you break ASM code in entry-common.S diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 5700a7ae7f0b..14e38261cd31 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -25,7 +25,6 @@ #include #include #include -#include #include #include @@ -918,8 +917,6 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno) audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3); - if (why == 0 && test_and_clear_thread_flag(TIF_SYSCALL_RESTARTSYS)) - scno = __NR_restart_syscall - __NR_SYSCALL_BASE; if (!test_thread_flag(TIF_SYSCALL_TRACE)) return scno; diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 6d3bce5bd7bc..536c5d6b340b 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -605,10 +605,12 @@ static void do_signal(struct pt_regs *regs, int syscall) case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: - case -ERESTART_RESTARTBLOCK: regs->ARM_r0 = regs->ARM_ORIG_r0; regs->ARM_pc = restart_addr; break; + case -ERESTART_RESTARTBLOCK: + regs->ARM_r0 = -EINTR; + break; } } @@ -624,14 +626,12 @@ static void do_signal(struct pt_regs *regs, int syscall) * debugger has chosen to restart at a different PC. */ if (regs->ARM_pc == restart_addr) { - if (retval == -ERESTARTNOHAND || - retval == -ERESTART_RESTARTBLOCK + if (retval == -ERESTARTNOHAND || (retval == -ERESTARTSYS && !(ka.sa.sa_flags & SA_RESTART))) { regs->ARM_r0 = -EINTR; regs->ARM_pc = continue_addr; } - clear_thread_flag(TIF_SYSCALL_RESTARTSYS); } handle_signal(signr, &ka, &info, regs); @@ -645,8 +645,29 @@ static void do_signal(struct pt_regs *regs, int syscall) * ignore the restart. */ if (retval == -ERESTART_RESTARTBLOCK - && regs->ARM_pc == restart_addr) - set_thread_flag(TIF_SYSCALL_RESTARTSYS); + && regs->ARM_pc == continue_addr) { + if (thumb_mode(regs)) { + regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; + regs->ARM_pc -= 2; + } else { +#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) + regs->ARM_r7 = __NR_restart_syscall; + regs->ARM_pc -= 4; +#else + u32 __user *usp; + + regs->ARM_sp -= 4; + usp = (u32 __user *)regs->ARM_sp; + + if (put_user(regs->ARM_pc, usp) == 0) { + regs->ARM_pc = KERN_RESTART_CODE; + } else { + regs->ARM_sp += 4; + force_sigsegv(0, current); + } +#endif + } + } } restore_saved_sigmask(); -- cgit v1.2.3 From fdeb8e35fd59e79dec385f98eb4b6d2e3398264b Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 4 Jul 2012 18:15:42 +0100 Subject: ARM: 7441/1: perf: return -EOPNOTSUPP if requested mode exclusion is unavailable We currently return -EPERM if the user requests mode exclusion that is not supported by the CPU. This looks pretty confusing from userspace and is inconsistent with other architectures (ppc, x86). This patch returns -EOPNOTSUPP instead. Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 186c8cb982c5..a02eada3aa5d 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -503,7 +503,7 @@ __hw_perf_event_init(struct perf_event *event) event_requires_mode_exclusion(&event->attr)) { pr_debug("ARM performance counters do not support " "mode exclusion\n"); - return -EPERM; + return -EOPNOTSUPP; } /* -- cgit v1.2.3 From f8b435bb918412c9410da4c4b0b02b6b3d99b27c Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Wed, 4 Jul 2012 07:37:37 +0100 Subject: ARM: 7440/1: kprobes: only test 'sub pc, pc, #1b-2b+8-2' on ARMv6 'sub pc, pc, #1b-2b+8-2' results in address<1:0> == '10'. sub pc, pc, #const (== ADR pc, #const) performs an interworking branch (BXWritePC()) on ARMv7+ and a simple branch (BranchWritePC()) on earlier versions. In ARM state, BXWritePC() is UNPREDICTABLE when address<1:0> == '10'. In ARM state on ARMv6+, BranchWritePC() ignores address<1:0>. Before ARMv6, BranchWritePC() is UNPREDICTABLE if address<1:0> != '00' So the instruction is UNPREDICTABLE both before and after v6. Acked-by: Jon Medhurst Signed-off-by: Rabin Vincent Signed-off-by: Russell King --- arch/arm/kernel/kprobes-test-arm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/kernel/kprobes-test-arm.c index ba32b393b3f0..38c1a3b103a0 100644 --- a/arch/arm/kernel/kprobes-test-arm.c +++ b/arch/arm/kernel/kprobes-test-arm.c @@ -187,8 +187,8 @@ void kprobe_arm_test_cases(void) TEST_BF_R ("mov pc, r",0,2f,"") TEST_BF_RR("mov pc, r",0,2f,", asl r",1,0,"") TEST_BB( "sub pc, pc, #1b-2b+8") -#if __LINUX_ARM_ARCH__ >= 6 - TEST_BB( "sub pc, pc, #1b-2b+8-2") /* UNPREDICTABLE before ARMv6 */ +#if __LINUX_ARM_ARCH__ == 6 && !defined(CONFIG_CPU_V7) + TEST_BB( "sub pc, pc, #1b-2b+8-2") /* UNPREDICTABLE before and after ARMv6 */ #endif TEST_BB_R( "sub pc, pc, r",14, 1f-2f+8,"") TEST_BB_R( "rsb pc, r",14,1f-2f+8,", pc") -- cgit v1.2.3