x86, mce: Get rid of TIF_MCE_NOTIFY and associated mce tricks (d4812e16) · Commits · 戴 / test

arch/x86/include/asm/mce.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -190,7 +190,6 @@ enum mcp_flags {
		void machine_check_poll(enum mcp_flags flags, mce_banks_t *b);

		int mce_notify_irq(void);
		void mce_notify_process(void);

		DECLARE_PER_CPU(struct mce, injectm);

arch/x86/include/asm/thread_info.h

+1 −3

Original line number	Diff line number	Diff line
		@@ -75,7 +75,6 @@ struct thread_info {
		#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
		#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
		#define TIF_SECCOMP 8 /* secure computing */
		#define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */
		#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
		#define TIF_UPROBE 12 /* breakpointed or singlestepping */
		#define TIF_NOTSC 16 /* TSC is not accessible in userland */
		@@ -100,7 +99,6 @@ struct thread_info {
		#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
		#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
		#define _TIF_SECCOMP (1 << TIF_SECCOMP)
		#define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY)
		#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
		#define _TIF_UPROBE (1 << TIF_UPROBE)
		#define _TIF_NOTSC (1 << TIF_NOTSC)
		@@ -140,7 +138,7 @@ struct thread_info {

		/* Only used for 64 bit */
		#define _TIF_DO_NOTIFY_MASK \
		(_TIF_SIGPENDING \| _TIF_MCE_NOTIFY \| _TIF_NOTIFY_RESUME \| \
		(_TIF_SIGPENDING \| _TIF_NOTIFY_RESUME \| \
		_TIF_USER_RETURN_NOTIFY \| _TIF_UPROBE)

		/* flags to check in __switch_to() */

arch/x86/kernel/cpu/mcheck/mce.c

+25 −84

Original line number	Diff line number	Diff line
		@@ -1003,51 +1003,6 @@ static void mce_clear_state(unsigned long *toclear)
		}
		}

		/*
		* Need to save faulting physical address associated with a process
		* in the machine check handler some place where we can grab it back
		* later in mce_notify_process()
		*/
		#define MCE_INFO_MAX 16

		struct mce_info {
		atomic_t inuse;
		struct task_struct *t;
		__u64 paddr;
		int restartable;
		} mce_info[MCE_INFO_MAX];

		static void mce_save_info(__u64 addr, int c)
		{
		struct mce_info *mi;

		for (mi = mce_info; mi < &mce_info[MCE_INFO_MAX]; mi++) {
		if (atomic_cmpxchg(&mi->inuse, 0, 1) == 0) {
		mi->t = current;
		mi->paddr = addr;
		mi->restartable = c;
		return;
		}
		}

		mce_panic("Too many concurrent recoverable errors", NULL, NULL);
		}

		static struct mce_info *mce_find_info(void)
		{
		struct mce_info *mi;

		for (mi = mce_info; mi < &mce_info[MCE_INFO_MAX]; mi++)
		if (atomic_read(&mi->inuse) && mi->t == current)
		return mi;
		return NULL;
		}

		static void mce_clear_info(struct mce_info *mi)
		{
		atomic_set(&mi->inuse, 0);
		}

		/*
		* The actual machine check handler. This only handles real
		* exceptions when something got corrupted coming in through int 18.
		@@ -1086,6 +1041,8 @@ void do_machine_check(struct pt_regs *regs, long error_code)
		DECLARE_BITMAP(toclear, MAX_NR_BANKS);
		DECLARE_BITMAP(valid_banks, MAX_NR_BANKS);
		char *msg = "Unknown";
		u64 recover_paddr = ~0ull;
		int flags = MF_ACTION_REQUIRED;

		prev_state = ist_enter(regs);

		@@ -1207,9 +1164,9 @@ void do_machine_check(struct pt_regs *regs, long error_code)
		if (no_way_out)
		mce_panic("Fatal machine check on current CPU", &m, msg);
		if (worst == MCE_AR_SEVERITY) {
		/* schedule action before return to userland */
		mce_save_info(m.addr, m.mcgstatus & MCG_STATUS_RIPV);
		set_thread_flag(TIF_MCE_NOTIFY);
		recover_paddr = m.addr;
		if (!(m.mcgstatus & MCG_STATUS_RIPV))
		flags \|= MF_MUST_KILL;
		} else if (kill_it) {
		force_sig(SIGBUS, current);
		}
		@@ -1220,6 +1177,26 @@ void do_machine_check(struct pt_regs *regs, long error_code)
		mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
		out:
		sync_core();

		if (recover_paddr == ~0ull)
		goto done;

		pr_err("Uncorrected hardware memory error in user-access at %llx",
		recover_paddr);
		/*
		* We must call memory_failure() here even if the current process is
		* doomed. We still need to mark the page as poisoned and alert any
		* other users of the page.
		*/
		ist_begin_non_atomic(regs);
		local_irq_enable();
		if (memory_failure(recover_paddr >> PAGE_SHIFT, MCE_VECTOR, flags) < 0) {
		pr_err("Memory error not recovered");
		force_sig(SIGBUS, current);
		}
		local_irq_disable();
		ist_end_non_atomic();
		done:
		ist_exit(regs, prev_state);
		}
		EXPORT_SYMBOL_GPL(do_machine_check);
		@@ -1237,42 +1214,6 @@ int memory_failure(unsigned long pfn, int vector, int flags)
		}
		#endif

		/*
		* Called in process context that interrupted by MCE and marked with
		* TIF_MCE_NOTIFY, just before returning to erroneous userland.
		* This code is allowed to sleep.
		* Attempt possible recovery such as calling the high level VM handler to
		* process any corrupted pages, and kill/signal current process if required.
		* Action required errors are handled here.
		*/
		void mce_notify_process(void)
		{
		unsigned long pfn;
		struct mce_info *mi = mce_find_info();
		int flags = MF_ACTION_REQUIRED;

		if (!mi)
		mce_panic("Lost physical address for unconsumed uncorrectable error", NULL, NULL);
		pfn = mi->paddr >> PAGE_SHIFT;

		clear_thread_flag(TIF_MCE_NOTIFY);

		pr_err("Uncorrected hardware memory error in user-access at %llx",
		mi->paddr);
		/*
		* We must call memory_failure() here even if the current process is
		* doomed. We still need to mark the page as poisoned and alert any
		* other users of the page.
		*/
		if (!mi->restartable)
		flags \|= MF_MUST_KILL;
		if (memory_failure(pfn, MCE_VECTOR, flags) < 0) {
		pr_err("Memory error not recovered");
		force_sig(SIGBUS, current);
		}
		mce_clear_info(mi);
		}

		/*
		* Action optional processing happens here (picking up
		* from the list of faulting pages that do_machine_check()

arch/x86/kernel/signal.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -740,12 +740,6 @@ do_notify_resume(struct pt_regs regs, void unused, __u32 thread_info_flags)
		{
		user_exit();

		#ifdef CONFIG_X86_MCE
		/* notify userspace of pending MCEs */
		if (thread_info_flags & _TIF_MCE_NOTIFY)
		mce_notify_process();
		#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */

		if (thread_info_flags & _TIF_UPROBE)
		uprobe_notify_resume(regs);

Admin message