[GIT PULL] x86 fixes

Ingo Molnar
2016-11-22T15:56:54Z

Linus,

Please pull the latest x86-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-for-linus

# HEAD: e5dce2868818ca8706924f7bdc7939d481eefab0 x86/platform/intel-mid: Rename platform_wdt to platform_mrfld_wdt

Misc fixes:

- two fixes to make (very) old Intel CPUs boot reliably
- fix the intel-mid driver and rename it
- two KASAN false positive fixes
- an FPU fix
- two sysfb fixes
- two build fixes related to new toolchain versions

Thanks,

Ingo

------------------>
Andy Lutomirski (2):
x86/traps: Ignore high word of regs->cs in early_fixup_exception()
x86/boot: Fail the boot if !M486 and CPUID is missing

Andy Shevchenko (2):
x86/platform/intel-mid: Register watchdog device after SCU
x86/platform/intel-mid: Rename platform_wdt to platform_mrfld_wdt

Arnd Bergmann (1):
x86/boot: Avoid warning for zero-filling .bss

David Herrmann (2):
x86/sysfb: Add support for 64bit EFI lfb_base
x86/sysfb: Fix lfb_size calculation

H.J. Lu (1):
x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as well

Josh Poimboeuf (2):
x86/unwind: Prevent KASAN false positive warnings in guess unwinder
x86/dumpstack: Prevent KASAN false positive warnings

Yu-cheng Yu (1):
x86/fpu: Fix invalid FPU ptrace state after execve()

arch/x86/boot/compressed/Makefile | 5 ++-
arch/x86/boot/cpu.c | 6 ++++
arch/x86/kernel/dumpstack.c | 2 +-
arch/x86/kernel/fpu/core.c | 16 ++++-----
arch/x86/kernel/head_32.S | 9 +++--
arch/x86/kernel/sysfb_simplefb.c | 39 +++++++++++++++++-----
arch/x86/kernel/unwind_guess.c | 8 +++--
arch/x86/mm/extable.c | 7 +++-
arch/x86/platform/intel-mid/device_libs/Makefile | 2 +-
.../{platform_wdt.c => platform_mrfld_wdt.c} | 34 +++++++++++++++----
10 files changed, 95 insertions(+), 33 deletions(-)
rename arch/x86/platform/intel-mid/device_libs/{platform_wdt.c => platform_mrfld_wdt.c} (65%)

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 536ccfcc01c6..34d9e15857c3 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -40,8 +40,8 @@ GCOV_PROFILE := n
UBSAN_SANITIZE :=n

LDFLAGS := -m elf_$(UTS_MACHINE)
-ifeq ($(CONFIG_RELOCATABLE),y)
-# If kernel is relocatable, build compressed kernel as PIE.
+# Compressed kernel should be built as PIE since it may be loaded at any
+# address by the bootloader.
ifeq ($(CONFIG_X86_32),y)
LDFLAGS += $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker)
else
@@ -51,7 +51,6 @@ else
LDFLAGS += $(shell $(LD) --help 2>&1 | grep -q "\-z noreloc-overflow" \
&& echo "-z noreloc-overflow -pie --no-dynamic-linker")
endif
-endif
LDFLAGS_vmlinux := -T

hostprogs-y := mkpiggy
diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c
index 26240dde081e..4224ede43b4e 100644
--- a/arch/x86/boot/cpu.c
+++ b/arch/x86/boot/cpu.c
@@ -87,6 +87,12 @@ int validate_cpu(void)
return -1;
}

+ if (CONFIG_X86_MINIMUM_CPU_FAMILY <= 4 && !IS_ENABLED(CONFIG_M486) &&
+ !has_eflag(X86_EFLAGS_ID)) {
+ printf("This kernel requires a CPU with the CPUID instruction. Build with CONFIG_M486=y to run on this CPU.\n");
+ return -1;
+ }
+
if (err_flags) {
puts("This kernel requires the following features "
"not present on the CPU:\n");
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 9b7cf5c28f5f..85f854b98a9d 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -112,7 +112,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
for (; stack < stack_info.end; stack++) {
unsigned long real_addr;
int reliable = 0;
- unsigned long addr = *stack;
+ unsigned long addr = READ_ONCE_NOCHECK(*stack);
unsigned long *ret_addr_p =
unwind_get_return_address_ptr(&state);

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 47004010ad5d..ebb4e95fbd74 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -521,14 +521,14 @@ void fpu__clear(struct fpu *fpu)
{
WARN_ON_FPU(fpu != &current->thread.fpu); /* Almost certainly an anomaly */

- if (!use_eager_fpu() || !static_cpu_has(X86_FEATURE_FPU)) {
- /* FPU state will be reallocated lazily at the first use. */
- fpu__drop(fpu);
- } else {
- if (!fpu->fpstate_active) {
- fpu__activate_curr(fpu);
- user_fpu_begin();
- }
+ fpu__drop(fpu);
+
+ /*
+ * Make sure fpstate is cleared and initialized.
+ */
+ if (static_cpu_has(X86_FEATURE_FPU)) {
+ fpu__activate_curr(fpu);
+ user_fpu_begin();
copy_init_fpstate_to_fpregs();
}
}
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index b6b2f0264af3..2dabea46f039 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -665,14 +665,17 @@ __PAGE_ALIGNED_BSS
initial_pg_pmd:
.fill 1024*KPMDS,4,0
#else
-ENTRY(initial_page_table)
+.globl initial_page_table
+initial_page_table:
.fill 1024,4,0
#endif
initial_pg_fixmap:
.fill 1024,4,0
-ENTRY(empty_zero_page)
+.globl empty_zero_page
+empty_zero_page:
.fill 4096,1,0
-ENTRY(swapper_pg_dir)
+.globl swapper_pg_dir
+swapper_pg_dir:
.fill 1024,4,0
EXPORT_SYMBOL(empty_zero_page)

diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
index 764a29f84de7..85195d447a92 100644
--- a/arch/x86/kernel/sysfb_simplefb.c
+++ b/arch/x86/kernel/sysfb_simplefb.c
@@ -66,13 +66,36 @@ __init int create_simplefb(const struct screen_info *si,
{
struct platform_device *pd;
struct resource res;
- unsigned long len;
+ u64 base, size;
+ u32 length;

- /* don't use lfb_size as it may contain the whole VMEM instead of only
- * the part that is occupied by the framebuffer */
- len = mode->height * mode->stride;
- len = PAGE_ALIGN(len);
- if (len > (u64)si->lfb_size << 16) {
+ /*
+ * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
+ * upper half of the base address. Assemble the address, then make sure
+ * it is valid and we can actually access it.
+ */
+ base = si->lfb_base;
+ if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ base |= (u64)si->ext_lfb_base << 32;
+ if (!base || (u64)(resource_size_t)base != base) {
+ printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
+ return -EINVAL;
+ }
+
+ /*
+ * Don't use lfb_size as IORESOURCE size, since it may contain the
+ * entire VMEM, and thus require huge mappings. Use just the part we
+ * need, that is, the part where the framebuffer is located. But verify
+ * that it does not exceed the advertised VMEM.
+ * Note that in case of VBE, the lfb_size is shifted by 16 bits for
+ * historical reasons.
+ */
+ size = si->lfb_size;
+ if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
+ size <<= 16;
+ length = mode->height * mode->stride;
+ length = PAGE_ALIGN(length);
+ if (length > size) {
printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
return -EINVAL;
}
@@ -81,8 +104,8 @@ __init int create_simplefb(const struct screen_info *si,
memset(&res, 0, sizeof(res));
res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
res.name = simplefb_resname;
- res.start = si->lfb_base;
- res.end = si->lfb_base + len - 1;
+ res.start = base;
+ res.end = res.start + length - 1;
if (res.end <= res.start)
return -EINVAL;

diff --git a/arch/x86/kernel/unwind_guess.c b/arch/x86/kernel/unwind_guess.c
index 2d721e533cf4..b80e8bf43cc6 100644
--- a/arch/x86/kernel/unwind_guess.c
+++ b/arch/x86/kernel/unwind_guess.c
@@ -7,11 +7,13 @@

unsigned long unwind_get_return_address(struct unwind_state *state)
{
+ unsigned long addr = READ_ONCE_NOCHECK(*state->sp);
+
if (unwind_done(state))
return 0;

return ftrace_graph_ret_addr(state->task, &state->graph_idx,
- *state->sp, state->sp);
+ addr, state->sp);
}
EXPORT_SYMBOL_GPL(unwind_get_return_address);

@@ -23,8 +25,10 @@ bool unwind_next_frame(struct unwind_state *state)
return false;

do {
+ unsigned long addr = READ_ONCE_NOCHECK(*state->sp);
+
for (state->sp++; state->sp < info->end; state->sp++)
- if (__kernel_text_address(*state->sp))
+ if (__kernel_text_address(addr))
return true;

state->sp = info->next_sp;
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 79ae939970d3..fcd06f7526de 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -135,7 +135,12 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
if (early_recursion_flag > 2)
goto halt_loop;

- if (regs->cs != __KERNEL_CS)
+ /*
+ * Old CPUs leave the high bits of CS on the stack
+ * undefined. I'm not sure which CPUs do this, but at least
+ * the 486 DX works this way.
+ */
+ if ((regs->cs & 0xFFFF) != __KERNEL_CS)
goto fail;

/*
diff --git a/arch/x86/platform/intel-mid/device_libs/Makefile b/arch/x86/platform/intel-mid/device_libs/Makefile
index 429d08be7848..dd6cfa4ad3ac 100644
--- a/arch/x86/platform/intel-mid/device_libs/Makefile
+++ b/arch/x86/platform/intel-mid/device_libs/Makefile
@@ -28,4 +28,4 @@ obj-$(subst m,y,$(CONFIG_GPIO_PCA953X)) += platform_pcal9555a.o
obj-$(subst m,y,$(CONFIG_GPIO_PCA953X)) += platform_tca6416.o
# MISC Devices
obj-$(subst m,y,$(CONFIG_KEYBOARD_GPIO)) += platform_gpio_keys.o
-obj-$(subst m,y,$(CONFIG_INTEL_MID_WATCHDOG)) += platform_wdt.o
+obj-$(subst m,y,$(CONFIG_INTEL_MID_WATCHDOG)) += platform_mrfld_wdt.o
diff --git a/arch/x86/platform/intel-mid/device_libs/platform_wdt.c b/arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c
similarity index 65%
rename from arch/x86/platform/intel-mid/device_libs/platform_wdt.c
rename to arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c
index de734134bc8d..3f1f1c77d090 100644
--- a/arch/x86/platform/intel-mid/device_libs/platform_wdt.c
+++ b/arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c
@@ -1,5 +1,5 @@
/*
- * platform_wdt.c: Watchdog platform library file
+ * Intel Merrifield watchdog platform device library file
*
* (C) Copyright 2014 Intel Corporation
* Author: David Cohen <david.a.cohen@linux.intel.com>
@@ -14,7 +14,9 @@
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/platform_data/intel-mid_wdt.h>
+
#include <asm/intel-mid.h>
+#include <asm/intel_scu_ipc.h>
#include <asm/io_apic.h>

#define TANGIER_EXT_TIMER0_MSI 15
@@ -50,14 +52,34 @@ static struct intel_mid_wdt_pdata tangier_pdata = {
.probe = tangier_probe,
};

-static int __init register_mid_wdt(void)
+static int wdt_scu_status_change(struct notifier_block *nb,
+ unsigned long code, void *data)
{
- if (intel_mid_identify_cpu() == INTEL_MID_CPU_CHIP_TANGIER) {
- wdt_dev.dev.platform_data = &tangier_pdata;
- return platform_device_register(&wdt_dev);
+ if (code == SCU_DOWN) {
+ platform_device_unregister(&wdt_dev);
+ return 0;
}

- return -ENODEV;
+ return platform_device_register(&wdt_dev);
}

+static struct notifier_block wdt_scu_notifier = {
+ .notifier_call = wdt_scu_status_change,
+};
+
+static int __init register_mid_wdt(void)
+{
+ if (intel_mid_identify_cpu() != INTEL_MID_CPU_CHIP_TANGIER)
+ return -ENODEV;
+
+ wdt_dev.dev.platform_data = &tangier_pdata;
+
+ /*
+ * We need to be sure that the SCU IPC is ready before watchdog device
+ * can be registered:
+ */
+ intel_scu_notifier_add(&wdt_scu_notifier);
+
+ return 0;
+}
rootfs_initcall(register_mid_wdt);