The following commit has been merged into the x86/cpu branch of tip: Commit-ID: 9998a9832c4027e907353e5e05fde730cf624b77 Gitweb: https://git.kernel.org/tip/9998a9832c4027e907353e5e05fde730cf624b77 Author: Ricardo Neri <ricardo.neri-calde...@linux.intel.com> AuthorDate: Sun, 26 Jul 2020 21:31:30 -07:00 Committer: Ingo Molnar <mi...@kernel.org> CommitterDate: Mon, 27 Jul 2020 12:42:06 +02:00
x86/cpu: Relocate sync_core() to sync_core.h Having sync_core() in processor.h is problematic since it is not possible to check for hardware capabilities via the *cpu_has() family of macros. The latter needs the definitions in processor.h. It also looks more intuitive to relocate the function to sync_core.h. This changeset does not make changes in functionality. Signed-off-by: Ricardo Neri <ricardo.neri-calde...@linux.intel.com> Signed-off-by: Ingo Molnar <mi...@kernel.org> Reviewed-by: Tony Luck <tony.l...@intel.com> Link: https://lore.kernel.org/r/20200727043132.15082-3-ricardo.neri-calde...@linux.intel.com --- arch/x86/include/asm/processor.h | 64 +---------------------------- arch/x86/include/asm/sync_core.h | 64 ++++++++++++++++++++++++++++- arch/x86/kernel/alternative.c | 1 +- arch/x86/kernel/cpu/mce/core.c | 1 +- drivers/misc/sgi-gru/grufault.c | 1 +- drivers/misc/sgi-gru/gruhandles.c | 1 +- drivers/misc/sgi-gru/grukservices.c | 1 +- 7 files changed, 69 insertions(+), 64 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 03b7c4c..68ba42f 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -678,70 +678,6 @@ static inline unsigned int cpuid_edx(unsigned int op) return edx; } -/* - * This function forces the icache and prefetched instruction stream to - * catch up with reality in two very specific cases: - * - * a) Text was modified using one virtual address and is about to be executed - * from the same physical page at a different virtual address. - * - * b) Text was modified on a different CPU, may subsequently be - * executed on this CPU, and you want to make sure the new version - * gets executed. This generally means you're calling this in a IPI. - * - * If you're calling this for a different reason, you're probably doing - * it wrong. - */ -static inline void sync_core(void) -{ - /* - * There are quite a few ways to do this. IRET-to-self is nice - * because it works on every CPU, at any CPL (so it's compatible - * with paravirtualization), and it never exits to a hypervisor. - * The only down sides are that it's a bit slow (it seems to be - * a bit more than 2x slower than the fastest options) and that - * it unmasks NMIs. The "push %cs" is needed because, in - * paravirtual environments, __KERNEL_CS may not be a valid CS - * value when we do IRET directly. - * - * In case NMI unmasking or performance ever becomes a problem, - * the next best option appears to be MOV-to-CR2 and an - * unconditional jump. That sequence also works on all CPUs, - * but it will fault at CPL3 (i.e. Xen PV). - * - * CPUID is the conventional way, but it's nasty: it doesn't - * exist on some 486-like CPUs, and it usually exits to a - * hypervisor. - * - * Like all of Linux's memory ordering operations, this is a - * compiler barrier as well. - */ -#ifdef CONFIG_X86_32 - asm volatile ( - "pushfl\n\t" - "pushl %%cs\n\t" - "pushl $1f\n\t" - "iret\n\t" - "1:" - : ASM_CALL_CONSTRAINT : : "memory"); -#else - unsigned int tmp; - - asm volatile ( - "mov %%ss, %0\n\t" - "pushq %q0\n\t" - "pushq %%rsp\n\t" - "addq $8, (%%rsp)\n\t" - "pushfq\n\t" - "mov %%cs, %0\n\t" - "pushq %q0\n\t" - "pushq $1f\n\t" - "iretq\n\t" - "1:" - : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory"); -#endif -} - extern void select_idle_routine(const struct cpuinfo_x86 *c); extern void amd_e400_c1e_apic_setup(void); diff --git a/arch/x86/include/asm/sync_core.h b/arch/x86/include/asm/sync_core.h index c67caaf..9c5573f 100644 --- a/arch/x86/include/asm/sync_core.h +++ b/arch/x86/include/asm/sync_core.h @@ -7,6 +7,70 @@ #include <asm/cpufeature.h> /* + * This function forces the icache and prefetched instruction stream to + * catch up with reality in two very specific cases: + * + * a) Text was modified using one virtual address and is about to be executed + * from the same physical page at a different virtual address. + * + * b) Text was modified on a different CPU, may subsequently be + * executed on this CPU, and you want to make sure the new version + * gets executed. This generally means you're calling this in a IPI. + * + * If you're calling this for a different reason, you're probably doing + * it wrong. + */ +static inline void sync_core(void) +{ + /* + * There are quite a few ways to do this. IRET-to-self is nice + * because it works on every CPU, at any CPL (so it's compatible + * with paravirtualization), and it never exits to a hypervisor. + * The only down sides are that it's a bit slow (it seems to be + * a bit more than 2x slower than the fastest options) and that + * it unmasks NMIs. The "push %cs" is needed because, in + * paravirtual environments, __KERNEL_CS may not be a valid CS + * value when we do IRET directly. + * + * In case NMI unmasking or performance ever becomes a problem, + * the next best option appears to be MOV-to-CR2 and an + * unconditional jump. That sequence also works on all CPUs, + * but it will fault at CPL3 (i.e. Xen PV). + * + * CPUID is the conventional way, but it's nasty: it doesn't + * exist on some 486-like CPUs, and it usually exits to a + * hypervisor. + * + * Like all of Linux's memory ordering operations, this is a + * compiler barrier as well. + */ +#ifdef CONFIG_X86_32 + asm volatile ( + "pushfl\n\t" + "pushl %%cs\n\t" + "pushl $1f\n\t" + "iret\n\t" + "1:" + : ASM_CALL_CONSTRAINT : : "memory"); +#else + unsigned int tmp; + + asm volatile ( + "mov %%ss, %0\n\t" + "pushq %q0\n\t" + "pushq %%rsp\n\t" + "addq $8, (%%rsp)\n\t" + "pushfq\n\t" + "mov %%cs, %0\n\t" + "pushq %q0\n\t" + "pushq $1f\n\t" + "iretq\n\t" + "1:" + : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory"); +#endif +} + +/* * Ensure that a core serializing instruction is issued before returning * to user-mode. x86 implements return to user-space through sysexit, * sysrel, and sysretq, which are not core serializing. diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 8fd39ff..6e63231 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -15,6 +15,7 @@ #include <linux/kprobes.h> #include <linux/mmu_context.h> #include <linux/bsearch.h> +#include <linux/sync_core.h> #include <asm/text-patching.h> #include <asm/alternative.h> #include <asm/sections.h> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 14e4b4d..9246595 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -42,6 +42,7 @@ #include <linux/export.h> #include <linux/jump_label.h> #include <linux/set_memory.h> +#include <linux/sync_core.h> #include <linux/task_work.h> #include <linux/hardirq.h> diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index b152111..7238255 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -20,6 +20,7 @@ #include <linux/io.h> #include <linux/uaccess.h> #include <linux/security.h> +#include <linux/sync_core.h> #include <linux/prefetch.h> #include "gru.h" #include "grutables.h" diff --git a/drivers/misc/sgi-gru/gruhandles.c b/drivers/misc/sgi-gru/gruhandles.c index f7224f9..1d75d5e 100644 --- a/drivers/misc/sgi-gru/gruhandles.c +++ b/drivers/misc/sgi-gru/gruhandles.c @@ -16,6 +16,7 @@ #define GRU_OPERATION_TIMEOUT (((cycles_t) local_cpu_data->itc_freq)*10) #define CLKS2NSEC(c) ((c) *1000000000 / local_cpu_data->itc_freq) #else +#include <linux/sync_core.h> #include <asm/tsc.h> #define GRU_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000) #define CLKS2NSEC(c) ((c) * 1000000 / tsc_khz) diff --git a/drivers/misc/sgi-gru/grukservices.c b/drivers/misc/sgi-gru/grukservices.c index 0197441..f6e600b 100644 --- a/drivers/misc/sgi-gru/grukservices.c +++ b/drivers/misc/sgi-gru/grukservices.c @@ -16,6 +16,7 @@ #include <linux/miscdevice.h> #include <linux/proc_fs.h> #include <linux/interrupt.h> +#include <linux/sync_core.h> #include <linux/uaccess.h> #include <linux/delay.h> #include <linux/export.h>
