Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - MCE related boot crash fix on certain AMD systems

   - FPU exception handling fix

   - FPU handling race fix

   - revert+rewrite of the RSDP boot protocol extension, use boot_params
     instead

   - documentation fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/MCE/AMD: Fix the thresholding machinery initialization order
  x86/fpu: Use the correct exception table macro in the XSTATE_OP wrapper
  x86/fpu: Disable bottom halves while loading FPU registers
  x86/acpi, x86/boot: Take RSDP address from boot params if available
  x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address to setup_header")
  x86/ptrace: Fix documentation for tracehook_report_syscall_entry()

12 files changed, 16 insertions, 82 deletions

diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 7727db8f94bc..5e9b826b5f62 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -61,18 +61,6 @@ Protocol 2.12:	(Kernel 3.8) Added the xloadflags field and extension fields
                 to struct boot_params for loading bzImage and ramdisk
                 above 4G in 64bit.
 
-Protocol 2.13:  (Kernel 3.14) Support 32- and 64-bit flags being set in
-                xloadflags to support booting a 64-bit kernel from 32-bit
-                EFI
-
-Protocol 2.14:  (Kernel 4.20) Added acpi_rsdp_addr holding the physical
-                address of the ACPI RSDP table.
-                The bootloader updates version with:
-                0x8000 | min(kernel-version, bootloader-version)
-                kernel-version being the protocol version supported by
-                the kernel and bootloader-version the protocol version
-                supported by the bootloader.
-
 **** MEMORY LAYOUT
 
 The traditional memory map for the kernel loader, used for Image or
@@ -209,7 +197,6 @@ Offset	Proto	Name		Meaning
 0258/8  2.10+   pref_address    Preferred loading address
 0260/4  2.10+   init_size       Linear memory required during initialization
 0264/4  2.11+   handover_offset Offset of handover entry point
-0268/8  2.14+   acpi_rsdp_addr  Physical address of RSDP table
 
 (1) For backwards compatibility, if the setup_sects field contains 0, the
     real value is 4.
@@ -322,7 +309,7 @@ Protocol:	2.00+
   Contains the magic number "HdrS" (0x53726448).
 
 Field name:     version
-Type:           modify
+Type:           read
 Offset/size:    0x206/2
 Protocol:       2.00+
 
@@ -330,12 +317,6 @@ Protocol:	2.00+
   e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version
   10.17.
 
-  Up to protocol version 2.13 this information is only read by the
-  bootloader. From protocol version 2.14 onwards the bootloader will
-  write the used protocol version or-ed with 0x8000 to the field. The
-  used protocol version will be the minimum of the supported protocol
-  versions of the bootloader and the kernel.
-
 Field name:     realmode_swtch
 Type:           modify (optional)
 Offset/size:    0x208/4
@@ -763,17 +744,6 @@ Offset/size:	0x264/4
 
   See EFI HANDOVER PROTOCOL below for more details.
 
-Field name:     acpi_rsdp_addr
-Type:           write
-Offset/size:    0x268/8
-Protocol:       2.14+
-
-  This field can be set by the boot loader to tell the kernel the
-  physical address of the ACPI RSDP table.
-
-  A value of 0 indicates the kernel should fall back to the standard
-  methods to locate the RSDP.
-
 
 **** THE IMAGE CHECKSUM
 
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 4c881c850125..850b8762e889 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -300,7 +300,7 @@ _start:
         # Part 2 of the header, from the old setup.S
 
                 .ascii  "HdrS"          # header signature
-                .word   0x020e          # header version number (>= 0x0105)
+                .word   0x020d          # header version number (>= 0x0105)
                                         # or else old loadlin-1.5 will fail)
                 .globl realmode_swtch
 realmode_swtch: .word   0, 0            # default_switch, SETUPSEG
@@ -558,10 +558,6 @@ pref_address:		.quad LOAD_PHYSICAL_ADDR	# preferred load addr
 init_size:              .long INIT_SIZE         # kernel initialization size
 handover_offset:        .long 0                 # Filled in by build.c
 
-acpi_rsdp_addr:         .quad 0                 # 64-bit physical pointer to the
-                                                # ACPI RSDP table, added with
-                                                # version 2.14
-
 # End of setup header #####################################################
 
         .section ".entrytext", "ax"
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 5f7290e6e954..69dcdf195b61 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -226,7 +226,7 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
                      "3: movl $-2,%[err]\n\t"                           \
                      "jmp 2b\n\t"                                       \
                      ".popsection\n\t"                                  \
-                     _ASM_EXTABLE_UA(1b, 3b)                            \
+                     _ASM_EXTABLE(1b, 3b)                               \
                      : [err] "=r" (err)                                 \
                      : "D" (st), "m" (*st), "a" (lmask), "d" (hmask)    \
                      : "memory")
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 0f842104862c..b85a7c54c6a1 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -303,6 +303,4 @@ extern void x86_init_noop(void);
 extern void x86_init_uint_noop(unsigned int unused);
 extern bool x86_pnpbios_disabled(void);
 
-void x86_verify_bootdata_version(void);
-
 #endif
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 22f89d040ddd..60733f137e9a 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -16,9 +16,6 @@
 #define RAMDISK_PROMPT_FLAG             0x8000
 #define RAMDISK_LOAD_FLAG               0x4000
 
-/* version flags */
-#define VERSION_WRITTEN 0x8000
-
 /* loadflags */
 #define LOADED_HIGH     (1<<0)
 #define KASLR_FLAG      (1<<1)
@@ -89,7 +86,6 @@ struct setup_header {
         __u64   pref_address;
         __u32   init_size;
         __u32   handover_offset;
-        __u64   acpi_rsdp_addr;
 } __attribute__((packed));
 
 struct sys_desc_table {
@@ -159,7 +155,8 @@ struct boot_params {
         __u8  _pad2[4];                                 /* 0x054 */
         __u64  tboot_addr;                              /* 0x058 */
         struct ist_info ist_info;                       /* 0x060 */
-        __u8  _pad3[16];                                /* 0x070 */
+        __u64 acpi_rsdp_addr;                           /* 0x070 */
+        __u8  _pad3[8];                                 /* 0x078 */
         __u8  hd0_info[16];     /* obsolete! */         /* 0x080 */
         __u8  hd1_info[16];     /* obsolete! */         /* 0x090 */
         struct sys_desc_table sys_desc_table; /* obsolete! */   /* 0x0a0 */
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 92c76bf97ad8..06635fbca81c 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1776,5 +1776,5 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size)
 
 u64 x86_default_get_root_pointer(void)
 {
-        return boot_params.hdr.acpi_rsdp_addr;
+        return boot_params.acpi_rsdp_addr;
 }
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index dd33c357548f..e12454e21b8a 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -56,7 +56,7 @@
 /* Threshold LVT offset is at MSR0xC0000410[15:12] */
 #define SMCA_THR_LVT_OFF        0xF000
 
-static bool thresholding_en;
+static bool thresholding_irq_en;
 
 static const char * const th_names[] = {
         "load_store",
@@ -534,9 +534,8 @@ prepare_threshold_block(unsigned int bank, unsigned int block, u32 addr,
 
 set_offset:
         offset = setup_APIC_mce_threshold(offset, new);
-
-        if ((offset == new) && (mce_threshold_vector != amd_threshold_interrupt))
-                mce_threshold_vector = amd_threshold_interrupt;
+        if (offset == new)
+                thresholding_irq_en = true;
 
 done:
         mce_threshold_block_init(&b, offset);
@@ -1357,9 +1356,6 @@ int mce_threshold_remove_device(unsigned int cpu)
 {
         unsigned int bank;
 
-        if (!thresholding_en)
-                return 0;
-
         for (bank = 0; bank < mca_cfg.banks; ++bank) {
                 if (!(per_cpu(bank_map, cpu) & (1 << bank)))
                         continue;
@@ -1377,9 +1373,6 @@ int mce_threshold_create_device(unsigned int cpu)
         struct threshold_bank **bp;
         int err = 0;
 
-        if (!thresholding_en)
-                return 0;
-
         bp = per_cpu(threshold_banks, cpu);
         if (bp)
                 return 0;
@@ -1408,9 +1401,6 @@ static __init int threshold_init_device(void)
 {
         unsigned lcpu = 0;
 
-        if (mce_threshold_vector == amd_threshold_interrupt)
-                thresholding_en = true;
-
         /* to hit CPUs online before the notifier is up */
         for_each_online_cpu(lcpu) {
                 int err = mce_threshold_create_device(lcpu);
@@ -1419,6 +1409,9 @@ static __init int threshold_init_device(void)
                         return err;
         }
 
+        if (thresholding_irq_en)
+                mce_threshold_vector = amd_threshold_interrupt;
+
         return 0;
 }
 /*
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 61a949d84dfa..d99a8ee9e185 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -344,10 +344,10 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                         sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
                 }
 
+                local_bh_disable();
                 fpu->initialized = 1;
-                preempt_disable();
                 fpu__restore(fpu);
-                preempt_enable();
+                local_bh_enable();
 
                 return err;
         } else {
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 76fa3b836598..ec6fefbfd3c0 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -37,7 +37,6 @@ asmlinkage __visible void __init i386_start_kernel(void)
         cr4_init_shadow();
 
         sanitize_boot_params(&boot_params);
-        x86_verify_bootdata_version();
 
         x86_early_init_platform_quirks();
 
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7663a8eb602b..16b1cbd3a61e 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -457,8 +457,6 @@ void __init x86_64_start_reservations(char *real_mode_data)
         if (!boot_params.hdr.version)
                 copy_bootdata(__va(real_mode_data));
 
-        x86_verify_bootdata_version();
-
         x86_early_init_platform_quirks();
 
         switch (boot_params.hdr.hardware_subarch) {
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index b74e7bfed6ab..d494b9bfe618 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1280,23 +1280,6 @@ void __init setup_arch(char **cmdline_p)
         unwind_init();
 }
 
-/*
- * From boot protocol 2.14 onwards we expect the bootloader to set the
- * version to "0x8000 | <used version>". In case we find a version >= 2.14
- * without the 0x8000 we assume the boot loader supports 2.13 only and
- * reset the version accordingly. The 0x8000 flag is removed in any case.
- */
-void __init x86_verify_bootdata_version(void)
-{
-        if (boot_params.hdr.version & VERSION_WRITTEN)
-                boot_params.hdr.version &= ~VERSION_WRITTEN;
-        else if (boot_params.hdr.version >= 0x020e)
-                boot_params.hdr.version = 0x020d;
-
-        if (boot_params.hdr.version < 0x020e)
-                boot_params.hdr.acpi_rsdp_addr = 0;
-}
-
 #ifdef CONFIG_X86_32
 
 static struct resource video_ram_resource = {
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 40b0b4c1bf7b..df20f8bdbfa3 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -83,8 +83,8 @@ static inline int ptrace_report_syscall(struct pt_regs *regs)
  * tracehook_report_syscall_entry - task is about to attempt a system call
  * @regs:               user register state of current task
  *
- * This will be called if %TIF_SYSCALL_TRACE has been set, when the
- * current task has just entered the kernel for a system call.
+ * This will be called if %TIF_SYSCALL_TRACE or %TIF_SYSCALL_EMU have been set,
+ * when the current task has just entered the kernel for a system call.
  * Full user register state is available here.  Changing the values
  * in @regs can affect the system call number and arguments to be tried.
  * It is safe to block here, preventing the system call from beginning.