From d7627467b7a8dd6944885290a03a07ceb28c10eb Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 17 Aug 2010 23:52:56 +0100 Subject: Make do_execve() take a const filename pointer Make do_execve() take a const filename pointer so that kernel_execve() compiles correctly on ARM: arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type This also requires the argv and envp arguments to be consted twice, once for the pointer array and once for the strings the array points to. This is because do_execve() passes a pointer to the filename (now const) to copy_strings_kernel(). A simpler alternative would be to cast the filename pointer in do_execve() when it's passed to copy_strings_kernel(). do_execve() may not change any of the strings it is passed as part of the argv or envp lists as they are some of them in .rodata, so marking these strings as const should be fine. Further kernel_execve() and sys_execve() need to be changed to match. This has been test built on x86_64, frv, arm and mips. Signed-off-by: David Howells Tested-by: Ralf Baechle Acked-by: Russell King Signed-off-by: Linus Torvalds --- arch/x86/include/asm/syscalls.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h index feb2ff9..f1d8b44 100644 --- a/arch/x86/include/asm/syscalls.h +++ b/arch/x86/include/asm/syscalls.h @@ -23,8 +23,9 @@ long sys_iopl(unsigned int, struct pt_regs *); /* kernel/process.c */ int sys_fork(struct pt_regs *); int sys_vfork(struct pt_regs *); -long sys_execve(const char __user *, char __user * __user *, - char __user * __user *, struct pt_regs *); +long sys_execve(const char __user *, + const char __user *const __user *, + const char __user *const __user *, struct pt_regs *); long sys_clone(unsigned long, unsigned long, void __user *, void __user *, struct pt_regs *); -- cgit v1.1 From fd89a137924e0710078c3ae855e7cec1c43cb845 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 16 Aug 2010 14:38:33 +0200 Subject: x86-32: Separate 1:1 pagetables from swapper_pg_dir This patch fixes machine crashes which occur when heavily exercising the CPU hotplug codepaths on a 32-bit kernel. These crashes are caused by AMD Erratum 383 and result in a fatal machine check exception. Here's the scenario: 1. On 32-bit, the swapper_pg_dir page table is used as the initial page table for booting a secondary CPU. 2. To make this work, swapper_pg_dir needs a direct mapping of physical memory in it (the low mappings). By adding those low, large page (2M) mappings (PAE kernel), we create the necessary conditions for Erratum 383 to occur. 3. Other CPUs which do not participate in the off- and onlining game may use swapper_pg_dir while the low mappings are present (when leave_mm is called). For all steps below, the CPU referred to is a CPU that is using swapper_pg_dir, and not the CPU which is being onlined. 4. The presence of the low mappings in swapper_pg_dir can result in TLB entries for addresses below __PAGE_OFFSET to be established speculatively. These TLB entries are marked global and large. 5. When the CPU with such TLB entry switches to another page table, this TLB entry remains because it is global. 6. The process then generates an access to an address covered by the above TLB entry but there is a permission mismatch - the TLB entry covers a large global page not accessible to userspace. 7. Due to this permission mismatch a new 4kb, user TLB entry gets established. Further, Erratum 383 provides for a small window of time where both TLB entries are present. This results in an uncorrectable machine check exception signalling a TLB multimatch which panics the machine. There are two ways to fix this issue: 1. Always do a global TLB flush when a new cr3 is loaded and the old page table was swapper_pg_dir. I consider this a hack hard to understand and with performance implications 2. Do not use swapper_pg_dir to boot secondary CPUs like 64-bit does. This patch implements solution 2. It introduces a trampoline_pg_dir which has the same layout as swapper_pg_dir with low_mappings. This page table is used as the initial page table of the booting CPU. Later in the bringup process, it switches to swapper_pg_dir and does a global TLB flush. This fixes the crashes in our test cases. -v2: switch to swapper_pg_dir right after entering start_secondary() so that we are able to access percpu data which might not be mapped in the trampoline page table. Signed-off-by: Joerg Roedel LKML-Reference: <20100816123833.GB28147@aftab> Signed-off-by: Borislav Petkov Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/pgtable_32.h | 1 + arch/x86/include/asm/trampoline.h | 3 +++ 2 files changed, 4 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h index 2984a25..f686f49 100644 --- a/arch/x86/include/asm/pgtable_32.h +++ b/arch/x86/include/asm/pgtable_32.h @@ -26,6 +26,7 @@ struct mm_struct; struct vm_area_struct; extern pgd_t swapper_pg_dir[1024]; +extern pgd_t trampoline_pg_dir[1024]; static inline void pgtable_cache_init(void) { } static inline void check_pgt_cache(void) { } diff --git a/arch/x86/include/asm/trampoline.h b/arch/x86/include/asm/trampoline.h index cb507bb..8f78fdf 100644 --- a/arch/x86/include/asm/trampoline.h +++ b/arch/x86/include/asm/trampoline.h @@ -13,14 +13,17 @@ extern unsigned char *trampoline_base; extern unsigned long init_rsp; extern unsigned long initial_code; +extern unsigned long initial_page_table; extern unsigned long initial_gs; #define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data, PAGE_SIZE) extern unsigned long setup_trampoline(void); +extern void __init setup_trampoline_page_table(void); extern void __init reserve_trampoline_memory(void); #else static inline void reserve_trampoline_memory(void) {}; +extern void __init setup_trampoline_page_table(void) {}; #endif /* CONFIG_X86_TRAMPOLINE */ #endif /* __ASSEMBLY__ */ -- cgit v1.1 From 8848a91068c018bc91f597038a0f41462a0f88a4 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Wed, 18 Aug 2010 11:42:23 -0700 Subject: x86-32: Fix dummy trampoline-related inline stubs Fix dummy inline stubs for trampoline-related functions when no trampolines exist (until we get rid of the no-trampoline case entirely.) Signed-off-by: H. Peter Anvin Cc: Joerg Roedel Cc: Borislav Petkov LKML-Reference: <4C6C294D.3030404@zytor.com> --- arch/x86/include/asm/trampoline.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/trampoline.h b/arch/x86/include/asm/trampoline.h index 8f78fdf..4dde797 100644 --- a/arch/x86/include/asm/trampoline.h +++ b/arch/x86/include/asm/trampoline.h @@ -22,8 +22,8 @@ extern unsigned long setup_trampoline(void); extern void __init setup_trampoline_page_table(void); extern void __init reserve_trampoline_memory(void); #else -static inline void reserve_trampoline_memory(void) {}; -extern void __init setup_trampoline_page_table(void) {}; +static inline void setup_trampoline_page_table(void) {} +static inline void reserve_trampoline_memory(void) {} #endif /* CONFIG_X86_TRAMPOLINE */ #endif /* __ASSEMBLY__ */ -- cgit v1.1 From cd7240c0b900eb6d690ccee088a6c9b46dae815a Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Thu, 19 Aug 2010 17:03:38 -0700 Subject: x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states TSC's get reset after suspend/resume (even on cpu's with invariant TSC which runs at a constant rate across ACPI P-, C- and T-states). And in some systems BIOS seem to reinit TSC to arbitrary large value (still sync'd across cpu's) during resume. This leads to a scenario of scheduler rq->clock (sched_clock_cpu()) less than rq->age_stamp (introduced in 2.6.32). This leads to a big value returned by scale_rt_power() and the resulting big group power set by the update_group_power() is causing improper load balancing between busy and idle cpu's after suspend/resume. This resulted in multi-threaded workloads (like kernel-compilation) go slower after suspend/resume cycle on core i5 laptops. Fix this by recomputing cyc2ns_offset's during resume, so that sched_clock() continues from the point where it was left off during suspend. Reported-by: Florian Pritz Signed-off-by: Suresh Siddha Cc: # [v2.6.32+] Signed-off-by: Peter Zijlstra LKML-Reference: <1282262618.2675.24.camel@sbsiddha-MOBL3.sc.intel.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/tsc.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index c042729..1ca132f 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -59,5 +59,7 @@ extern void check_tsc_sync_source(int cpu); extern void check_tsc_sync_target(void); extern int notsc_setup(char *); +extern void save_sched_clock_state(void); +extern void restore_sched_clock_state(void); #endif /* _ASM_X86_TSC_H */ -- cgit v1.1