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

Pull x86 fixes from Ingo Molnar:
 "This fixes 3 FPU handling related bugs, an EFI boot crash and a
  runtime warning.

  The EFI fix arrived late but I didn't want to delay it to after v4.5
  because the effects are pretty bad for the systems that are affected
  by it"

[ Actually, I don't think the EFI fix really matters yet, because we
  haven't switched to the separate EFI page tables in mainline yet ]

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Fix boot crash by always mapping boot service regions into new EFI page tables
  x86/fpu: Fix eager-FPU handling on legacy FPU machines
  x86/delay: Avoid preemptible context checks in delay_mwaitx()
  x86/fpu: Revert ("x86/fpu: Disable AVX when eagerfpu is off")
  x86/fpu: Fix 'no387' regression

5 files changed, 79 insertions, 37 deletions

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index af30fdeb140d..f23cd8c80b1c 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -20,16 +20,15 @@
 
 /* Supported features which support lazy state saving */
 #define XFEATURE_MASK_LAZY      (XFEATURE_MASK_FP | \
-                                 XFEATURE_MASK_SSE)
-
-/* Supported features which require eager state saving */
-#define XFEATURE_MASK_EAGER     (XFEATURE_MASK_BNDREGS | \
-                                 XFEATURE_MASK_BNDCSR | \
+                                 XFEATURE_MASK_SSE | \
                                  XFEATURE_MASK_YMM | \
                                  XFEATURE_MASK_OPMASK | \
                                  XFEATURE_MASK_ZMM_Hi256 | \
                                  XFEATURE_MASK_Hi16_ZMM)
 
+/* Supported features which require eager state saving */
+#define XFEATURE_MASK_EAGER     (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR)
+
 /* All currently supported features */
 #define XCNTXT_MASK     (XFEATURE_MASK_LAZY | XFEATURE_MASK_EAGER)
 
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index d25097c3fc1d..d5804adfa6da 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -409,8 +409,10 @@ static inline void copy_init_fpstate_to_fpregs(void)
 {
         if (use_xsave())
                 copy_kernel_to_xregs(&init_fpstate.xsave, -1);
-        else
+        else if (static_cpu_has(X86_FEATURE_FXSR))
                 copy_kernel_to_fxregs(&init_fpstate.fxsave);
+        else
+                copy_kernel_to_fregs(&init_fpstate.fsave);
 }
 
 /*
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 6d9f0a7ef4c8..bd08fb77073d 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -78,13 +78,15 @@ static void fpu__init_system_early_generic(struct cpuinfo_x86 *c)
         cr0 &= ~(X86_CR0_TS | X86_CR0_EM);
         write_cr0(cr0);
 
-        asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
-                     : "+m" (fsw), "+m" (fcw));
+        if (!test_bit(X86_FEATURE_FPU, (unsigned long *)cpu_caps_cleared)) {
+                asm volatile("fninit ; fnstsw %0 ; fnstcw %1"
+                             : "+m" (fsw), "+m" (fcw));
 
-        if (fsw == 0 && (fcw & 0x103f) == 0x003f)
-                set_cpu_cap(c, X86_FEATURE_FPU);
-        else
-                clear_cpu_cap(c, X86_FEATURE_FPU);
+                if (fsw == 0 && (fcw & 0x103f) == 0x003f)
+                        set_cpu_cap(c, X86_FEATURE_FPU);
+                else
+                        clear_cpu_cap(c, X86_FEATURE_FPU);
+        }
 
 #ifndef CONFIG_MATH_EMULATION
         if (!cpu_has_fpu) {
@@ -132,7 +134,7 @@ static void __init fpu__init_system_generic(void)
          * Set up the legacy init FPU context. (xstate init might overwrite this
          * with a more modern format, if the CPU supports it.)
          */
-        fpstate_init_fxstate(&init_fpstate.fxsave);
+        fpstate_init(&init_fpstate);
 
         fpu__init_system_mxcsr();
 }
@@ -300,12 +302,6 @@ u64 __init fpu__get_supported_xfeatures_mask(void)
 static void __init fpu__clear_eager_fpu_features(void)
 {
         setup_clear_cpu_cap(X86_FEATURE_MPX);
-        setup_clear_cpu_cap(X86_FEATURE_AVX);
-        setup_clear_cpu_cap(X86_FEATURE_AVX2);
-        setup_clear_cpu_cap(X86_FEATURE_AVX512F);
-        setup_clear_cpu_cap(X86_FEATURE_AVX512PF);
-        setup_clear_cpu_cap(X86_FEATURE_AVX512ER);
-        setup_clear_cpu_cap(X86_FEATURE_AVX512CD);
 }
 
 /*
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index e912b2f6d36e..2f07c291dcc8 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -102,7 +102,7 @@ static void delay_mwaitx(unsigned long __loops)
                  * Use cpu_tss as a cacheline-aligned, seldomly
                  * accessed per-cpu variable as the monitor target.
                  */
-                __monitorx(this_cpu_ptr(&cpu_tss), 0, 0);
+                __monitorx(raw_cpu_ptr(&cpu_tss), 0, 0);
 
                 /*
                  * AMD, like Intel, supports the EAX hint and EAX=0xf
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 2d66db8f80f9..ed30e79347e8 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -131,6 +131,27 @@ efi_status_t efi_query_variable_store(u32 attributes, unsigned long size)
 EXPORT_SYMBOL_GPL(efi_query_variable_store);
 
 /*
+ * Helper function for efi_reserve_boot_services() to figure out if we
+ * can free regions in efi_free_boot_services().
+ *
+ * Use this function to ensure we do not free regions owned by somebody
+ * else. We must only reserve (and then free) regions:
+ *
+ * - Not within any part of the kernel
+ * - Not the BIOS reserved area (E820_RESERVED, E820_NVS, etc)
+ */
+static bool can_free_region(u64 start, u64 size)
+{
+        if (start + size > __pa_symbol(_text) && start <= __pa_symbol(_end))
+                return false;
+
+        if (!e820_all_mapped(start, start+size, E820_RAM))
+                return false;
+
+        return true;
+}
+
+/*
  * The UEFI specification makes it clear that the operating system is free to do
  * whatever it wants with boot services code after ExitBootServices() has been
  * called. Ignoring this recommendation a significant bunch of EFI implementations 
@@ -147,26 +168,50 @@ void __init efi_reserve_boot_services(void)
                 efi_memory_desc_t *md = p;
                 u64 start = md->phys_addr;
                 u64 size = md->num_pages << EFI_PAGE_SHIFT;
+                bool already_reserved;
 
                 if (md->type != EFI_BOOT_SERVICES_CODE &&
                     md->type != EFI_BOOT_SERVICES_DATA)
                         continue;
-                /* Only reserve where possible:
-                 * - Not within any already allocated areas
-                 * - Not over any memory area (really needed, if above?)
-                 * - Not within any part of the kernel
-                 * - Not the bios reserved area
-                */
-                if ((start + size > __pa_symbol(_text)
-                                && start <= __pa_symbol(_end)) ||
-                        !e820_all_mapped(start, start+size, E820_RAM) ||
-                        memblock_is_region_reserved(start, size)) {
-                        /* Could not reserve, skip it */
-                        md->num_pages = 0;
-                        memblock_dbg("Could not reserve boot range [0x%010llx-0x%010llx]\n",
-                                     start, start+size-1);
-                } else
+
+                already_reserved = memblock_is_region_reserved(start, size);
+
+                /*
+                 * Because the following memblock_reserve() is paired
+                 * with free_bootmem_late() for this region in
+                 * efi_free_boot_services(), we must be extremely
+                 * careful not to reserve, and subsequently free,
+                 * critical regions of memory (like the kernel image) or
+                 * those regions that somebody else has already
+                 * reserved.
+                 *
+                 * A good example of a critical region that must not be
+                 * freed is page zero (first 4Kb of memory), which may
+                 * contain boot services code/data but is marked
+                 * E820_RESERVED by trim_bios_range().
+                 */
+                if (!already_reserved) {
                         memblock_reserve(start, size);
+
+                        /*
+                         * If we are the first to reserve the region, no
+                         * one else cares about it. We own it and can
+                         * free it later.
+                         */
+                        if (can_free_region(start, size))
+                                continue;
+                }
+
+                /*
+                 * We don't own the region. We must not free it.
+                 *
+                 * Setting this bit for a boot services region really
+                 * doesn't make sense as far as the firmware is
+                 * concerned, but it does provide us with a way to tag
+                 * those regions that must not be paired with
+                 * free_bootmem_late().
+                 */
+                md->attribute |= EFI_MEMORY_RUNTIME;
         }
 }
 
@@ -183,8 +228,8 @@ void __init efi_free_boot_services(void)
                     md->type != EFI_BOOT_SERVICES_DATA)
                         continue;
 
-                /* Could not reserve boot area */
-                if (!size)
+                /* Do not free, someone else owns it: */
+                if (md->attribute & EFI_MEMORY_RUNTIME)
                         continue;
 
                 free_bootmem_late(start, size);