[GIT pull] x86/fpu for 5.3-rc1

From: Thomas Gleixner
Date: Mon Jul 08 2019 - 05:23:05 EST

Linus,

please pull the latest x86-fpu-for-linus git tree from:

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

up to: 7891bc0ab739: x86/fpu: Inline fpu__xstate_clear_all_cpu_caps()

A small set of updates for the FPU code:

- Make the no387/nofxsr command line options useful by restricting them
to 32bit and actually clearing all dependencies to prevent random
crashes and malfunction.

- Simplify and cleanup the kernel_fpu_*() helpers

Thanks,

tglx

------------------>
Christoph Hellwig (3):
x86/fpu: Simplify kernel_fpu_end()
x86/fpu: Simplify kernel_fpu_begin()
x86/fpu: Remove the fpu__save() export

Sebastian Andrzej Siewior (2):
x86/fpu: Make 'no387' and 'nofxsr' command line options useful
x86/fpu: Inline fpu__xstate_clear_all_cpu_caps()


arch/x86/include/asm/fpu/xstate.h | 1 -
arch/x86/kernel/cpu/cpuid-deps.c | 5 ++++
arch/x86/kernel/fpu/core.c | 52 +++++++++++----------------------------
arch/x86/kernel/fpu/init.c | 19 ++++++--------
arch/x86/kernel/fpu/xstate.c | 11 +--------
5 files changed, 29 insertions(+), 59 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 7e42b285c856..c6136d79f8c0 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -47,7 +47,6 @@ extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
extern void __init update_regset_xstate_info(unsigned int size,
u64 xstate_mask);

-void fpu__xstate_clear_all_cpu_caps(void);
void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
const void *get_xsave_field_ptr(int xfeature_nr);
int using_compacted_format(void);
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 2c0bd38a44ab..e794e3860fc8 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -20,6 +20,7 @@ struct cpuid_dep {
* but it's difficult to tell that to the init reference checker.
*/
static const struct cpuid_dep cpuid_deps[] = {
+ { X86_FEATURE_FXSR, X86_FEATURE_FPU },
{ X86_FEATURE_XSAVEOPT, X86_FEATURE_XSAVE },
{ X86_FEATURE_XSAVEC, X86_FEATURE_XSAVE },
{ X86_FEATURE_XSAVES, X86_FEATURE_XSAVE },
@@ -27,7 +28,11 @@ static const struct cpuid_dep cpuid_deps[] = {
{ X86_FEATURE_PKU, X86_FEATURE_XSAVE },
{ X86_FEATURE_MPX, X86_FEATURE_XSAVE },
{ X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE },
+ { X86_FEATURE_CMOV, X86_FEATURE_FXSR },
+ { X86_FEATURE_MMX, X86_FEATURE_FXSR },
+ { X86_FEATURE_MMXEXT, X86_FEATURE_MMX },
{ X86_FEATURE_FXSR_OPT, X86_FEATURE_FXSR },
+ { X86_FEATURE_XSAVE, X86_FEATURE_FXSR },
{ X86_FEATURE_XMM, X86_FEATURE_FXSR },
{ X86_FEATURE_XMM2, X86_FEATURE_XMM },
{ X86_FEATURE_XMM3, X86_FEATURE_XMM2 },
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 649fbc3fcf9f..12c70840980e 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -43,18 +43,6 @@ static DEFINE_PER_CPU(bool, in_kernel_fpu);
*/
DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);

-static void kernel_fpu_disable(void)
-{
- WARN_ON_FPU(this_cpu_read(in_kernel_fpu));
- this_cpu_write(in_kernel_fpu, true);
-}
-
-static void kernel_fpu_enable(void)
-{
- WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
- this_cpu_write(in_kernel_fpu, false);
-}
-
static bool kernel_fpu_disabled(void)
{
return this_cpu_read(in_kernel_fpu);
@@ -94,42 +82,33 @@ bool irq_fpu_usable(void)
}
EXPORT_SYMBOL(irq_fpu_usable);

-static void __kernel_fpu_begin(void)
+void kernel_fpu_begin(void)
{
- struct fpu *fpu = &current->thread.fpu;
+ preempt_disable();

WARN_ON_FPU(!irq_fpu_usable());
+ WARN_ON_FPU(this_cpu_read(in_kernel_fpu));

- kernel_fpu_disable();
+ this_cpu_write(in_kernel_fpu, true);

- if (!(current->flags & PF_KTHREAD)) {
- if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
- set_thread_flag(TIF_NEED_FPU_LOAD);
- /*
- * Ignore return value -- we don't care if reg state
- * is clobbered.
- */
- copy_fpregs_to_fpstate(fpu);
- }
+ if (!(current->flags & PF_KTHREAD) &&
+ !test_thread_flag(TIF_NEED_FPU_LOAD)) {
+ set_thread_flag(TIF_NEED_FPU_LOAD);
+ /*
+ * Ignore return value -- we don't care if reg state
+ * is clobbered.
+ */
+ copy_fpregs_to_fpstate(&current->thread.fpu);
}
__cpu_invalidate_fpregs_state();
}
-
-static void __kernel_fpu_end(void)
-{
- kernel_fpu_enable();
-}
-
-void kernel_fpu_begin(void)
-{
- preempt_disable();
- __kernel_fpu_begin();
-}
EXPORT_SYMBOL_GPL(kernel_fpu_begin);

void kernel_fpu_end(void)
{
- __kernel_fpu_end();
+ WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
+
+ this_cpu_write(in_kernel_fpu, false);
preempt_enable();
}
EXPORT_SYMBOL_GPL(kernel_fpu_end);
@@ -155,7 +134,6 @@ void fpu__save(struct fpu *fpu)
trace_x86_fpu_after_save(fpu);
fpregs_unlock();
}
-EXPORT_SYMBOL_GPL(fpu__save);

/*
* Legacy x87 fpstate state init:
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index ef0030e3fe6b..6ce7e0a23268 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -204,12 +204,6 @@ static void __init fpu__init_system_xstate_size_legacy(void)
*/

if (!boot_cpu_has(X86_FEATURE_FPU)) {
- /*
- * Disable xsave as we do not support it if i387
- * emulation is enabled.
- */
- setup_clear_cpu_cap(X86_FEATURE_XSAVE);
- setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
fpu_kernel_xstate_size = sizeof(struct swregs_state);
} else {
if (boot_cpu_has(X86_FEATURE_FXSR))
@@ -252,17 +246,20 @@ static void __init fpu__init_parse_early_param(void)
char *argptr = arg;
int bit;

+#ifdef CONFIG_X86_32
if (cmdline_find_option_bool(boot_command_line, "no387"))
+#ifdef CONFIG_MATH_EMULATION
setup_clear_cpu_cap(X86_FEATURE_FPU);
+#else
+ pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");
+#endif

- if (cmdline_find_option_bool(boot_command_line, "nofxsr")) {
+ if (cmdline_find_option_bool(boot_command_line, "nofxsr"))
setup_clear_cpu_cap(X86_FEATURE_FXSR);
- setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);
- setup_clear_cpu_cap(X86_FEATURE_XMM);
- }
+#endif

if (cmdline_find_option_bool(boot_command_line, "noxsave"))
- fpu__xstate_clear_all_cpu_caps();
+ setup_clear_cpu_cap(X86_FEATURE_XSAVE);

if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 3c36dd1784db..7b4c52aa929f 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -67,15 +67,6 @@ static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
*/
unsigned int fpu_user_xstate_size;

-/*
- * Clear all of the X86_FEATURE_* bits that are unavailable
- * when the CPU has no XSAVE support.
- */
-void fpu__xstate_clear_all_cpu_caps(void)
-{
- setup_clear_cpu_cap(X86_FEATURE_XSAVE);
-}
-
/*
* Return whether the system supports a given xfeature.
*
@@ -709,7 +700,7 @@ static void fpu__init_disable_system_xstate(void)
{
xfeatures_mask = 0;
cr4_clear_bits(X86_CR4_OSXSAVE);
- fpu__xstate_clear_all_cpu_caps();
+ setup_clear_cpu_cap(X86_FEATURE_XSAVE);
}

/*