Commit 015b3155 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86-urgent-2020-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 fixes from Ingo Molnar:

 - more generic entry code ABI fallout

 - debug register handling bugfixes

 - fix vmalloc mappings on 32-bit kernels

 - kprobes instrumentation output fix on 32-bit kernels

 - fix over-eager WARN_ON_ONCE() on !SMAP hardware

 - NUMA debugging fix

 - fix Clang related crash on !RETPOLINE kernels

* tag 'x86-urgent-2020-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry: Unbreak 32bit fast syscall
  x86/debug: Allow a single level of #DB recursion
  x86/entry: Fix AC assertion
  tracing/kprobes, x86/ptrace: Fix regs argument order for i386
  x86, fakenuma: Fix invalid starting node ID
  x86/mm/32: Bring back vmalloc faulting on x86_32
  x86/cmdline: Disable jump tables for cmdline.c
parents 68beef57 4facb95b

arch/x86/entry/common.c

+20 −9
Original line number Diff line number Diff line
@@ -60,16 +60,10 @@ __visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs) 
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)

static __always_inline unsigned int syscall_32_enter(struct pt_regs *regs)

{

	unsigned int nr = (unsigned int)regs->orig_ax;



	if (IS_ENABLED(CONFIG_IA32_EMULATION))

		current_thread_info()->status |= TS_COMPAT;

	/*

	 * Subtlety here: if ptrace pokes something larger than 2^32-1 into

	 * orig_ax, the unsigned int return value truncates it.  This may

	 * or may not be necessary, but it matches the old asm behavior.

	 */

	return (unsigned int)syscall_enter_from_user_mode(regs, nr);



	return (unsigned int)regs->orig_ax;

}



/*
@@ -91,6 +85,13 @@ __visible noinstr void do_int80_syscall_32(struct pt_regs *regs) 
{

	unsigned int nr = syscall_32_enter(regs);



	/*

	 * Subtlety here: if ptrace pokes something larger than 2^32-1 into

	 * orig_ax, the unsigned int return value truncates it.  This may

	 * or may not be necessary, but it matches the old asm behavior.

	 */

	nr = (unsigned int)syscall_enter_from_user_mode(regs, nr);



	do_syscall_32_irqs_on(regs, nr);

	syscall_exit_to_user_mode(regs);

}
@@ -100,6 +101,13 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs) 
	unsigned int nr = syscall_32_enter(regs);

	int res;



	/*

	 * This cannot use syscall_enter_from_user_mode() as it has to

	 * fetch EBP before invoking any of the syscall entry work

	 * functions.

	 */

	syscall_enter_from_user_mode_prepare(regs);



	instrumentation_begin();

	/* Fetch EBP from where the vDSO stashed it. */

	if (IS_ENABLED(CONFIG_X86_64)) {
@@ -122,6 +130,9 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs) 
		return false;

	}



	/* The case truncates any ptrace induced syscall nr > 2^32 -1 */

	nr = (unsigned int)syscall_enter_from_user_mode_work(regs, nr);



	/* Now this is just like a normal syscall. */

	do_syscall_32_irqs_on(regs, nr);

	syscall_exit_to_user_mode(regs);

arch/x86/include/asm/entry-common.h

+10 −2
Original line number Diff line number Diff line
@@ -18,8 +18,16 @@ static __always_inline void arch_check_user_regs(struct pt_regs *regs) 
		 * state, not the interrupt state as imagined by Xen.

		 */

		unsigned long flags = native_save_fl();

		WARN_ON_ONCE(flags & (X86_EFLAGS_AC | X86_EFLAGS_DF |

				      X86_EFLAGS_NT));

		unsigned long mask = X86_EFLAGS_DF | X86_EFLAGS_NT;



		/*

		 * For !SMAP hardware we patch out CLAC on entry.

		 */

		if (boot_cpu_has(X86_FEATURE_SMAP) ||

		    (IS_ENABLED(CONFIG_64_BIT) && boot_cpu_has(X86_FEATURE_XENPV)))

			mask |= X86_EFLAGS_AC;



		WARN_ON_ONCE(flags & mask);



		/* We think we came from user mode. Make sure pt_regs agrees. */

		WARN_ON_ONCE(!user_mode(regs));

arch/x86/include/asm/ptrace.h

+1 −1
Original line number Diff line number Diff line
@@ -327,8 +327,8 @@ static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, 
	static const unsigned int argument_offs[] = {

#ifdef __i386__

		offsetof(struct pt_regs, ax),

		offsetof(struct pt_regs, cx),

		offsetof(struct pt_regs, dx),

		offsetof(struct pt_regs, cx),

#define NR_REG_ARGUMENTS 3

#else

		offsetof(struct pt_regs, di),

arch/x86/kernel/traps.c

+31 −34
Original line number Diff line number Diff line
@@ -729,20 +729,9 @@ static bool is_sysenter_singlestep(struct pt_regs *regs) 
#endif

}



static __always_inline void debug_enter(unsigned long *dr6, unsigned long *dr7)

static __always_inline unsigned long debug_read_clear_dr6(void)

{

	/*

	 * Disable breakpoints during exception handling; recursive exceptions

	 * are exceedingly 'fun'.

	 *

	 * Since this function is NOKPROBE, and that also applies to

	 * HW_BREAKPOINT_X, we can't hit a breakpoint before this (XXX except a

	 * HW_BREAKPOINT_W on our stack)

	 *

	 * Entry text is excluded for HW_BP_X and cpu_entry_area, which

	 * includes the entry stack is excluded for everything.

	 */

	*dr7 = local_db_save();

	unsigned long dr6;



	/*

	 * The Intel SDM says:
@@ -755,15 +744,12 @@ static __always_inline void debug_enter(unsigned long *dr6, unsigned long *dr7) 
	 *

	 * Keep it simple: clear DR6 immediately.

	 */

	get_debugreg(*dr6, 6);

	get_debugreg(dr6, 6);

	set_debugreg(0, 6);

	/* Filter out all the reserved bits which are preset to 1 */

	*dr6 &= ~DR6_RESERVED;

}

	dr6 &= ~DR6_RESERVED;



static __always_inline void debug_exit(unsigned long dr7)

{

	local_db_restore(dr7);

	return dr6;

}



/*
@@ -863,6 +849,18 @@ out: 
static __always_inline void exc_debug_kernel(struct pt_regs *regs,

					     unsigned long dr6)

{

	/*

	 * Disable breakpoints during exception handling; recursive exceptions

	 * are exceedingly 'fun'.

	 *

	 * Since this function is NOKPROBE, and that also applies to

	 * HW_BREAKPOINT_X, we can't hit a breakpoint before this (XXX except a

	 * HW_BREAKPOINT_W on our stack)

	 *

	 * Entry text is excluded for HW_BP_X and cpu_entry_area, which

	 * includes the entry stack is excluded for everything.

	 */

	unsigned long dr7 = local_db_save();

	bool irq_state = idtentry_enter_nmi(regs);

	instrumentation_begin();
@@ -883,6 +881,8 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, 


	instrumentation_end();

	idtentry_exit_nmi(regs, irq_state);



	local_db_restore(dr7);

}



static __always_inline void exc_debug_user(struct pt_regs *regs,
@@ -894,6 +894,15 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, 
	 */

	WARN_ON_ONCE(!user_mode(regs));



	/*

	 * NB: We can't easily clear DR7 here because

	 * idtentry_exit_to_usermode() can invoke ptrace, schedule, access

	 * user memory, etc.  This means that a recursive #DB is possible.  If

	 * this happens, that #DB will hit exc_debug_kernel() and clear DR7.

	 * Since we're not on the IST stack right now, everything will be

	 * fine.

	 */



	irqentry_enter_from_user_mode(regs);

	instrumentation_begin();
@@ -907,36 +916,24 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, 
/* IST stack entry */

DEFINE_IDTENTRY_DEBUG(exc_debug)

{

	unsigned long dr6, dr7;



	debug_enter(&dr6, &dr7);

	exc_debug_kernel(regs, dr6);

	debug_exit(dr7);

	exc_debug_kernel(regs, debug_read_clear_dr6());

}



/* User entry, runs on regular task stack */

DEFINE_IDTENTRY_DEBUG_USER(exc_debug)

{

	unsigned long dr6, dr7;



	debug_enter(&dr6, &dr7);

	exc_debug_user(regs, dr6);

	debug_exit(dr7);

	exc_debug_user(regs, debug_read_clear_dr6());

}

#else

/* 32 bit does not have separate entry points. */

DEFINE_IDTENTRY_RAW(exc_debug)

{

	unsigned long dr6, dr7;



	debug_enter(&dr6, &dr7);

	unsigned long dr6 = debug_read_clear_dr6();



	if (user_mode(regs))

		exc_debug_user(regs, dr6);

	else

		exc_debug_kernel(regs, dr6);



	debug_exit(dr7);

}

#endif

arch/x86/lib/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ ifdef CONFIG_FUNCTION_TRACER 
CFLAGS_REMOVE_cmdline.o = -pg

endif



CFLAGS_cmdline.o := -fno-stack-protector

CFLAGS_cmdline.o := -fno-stack-protector -fno-jump-tables

endif



inat_tables_script = $(srctree)/arch/x86/tools/gen-insn-attr-x86.awk

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