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Message-ID: <20141209123138.GA29062@gmail.com>
Date: Tue, 9 Dec 2014 13:31:38 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/asm tree changes for v3.19
Linus,
Please pull the latest x86-asm-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-asm-for-linus
# HEAD: 3736708f034ae1e8c62789ed737e8b90d5b40210 x86: Replace seq_printf() with seq_puts()
Misc changes:
- context switch micro-optimization
- debug printout micro-optimization
- comment enhancements and typo fix
Thanks,
Ingo
------------------>
Andy Lutomirski (2):
sched/x86_64: Don't save flags on context switch
sched/x86: Add a comment clarifying LDT context switching
Nicholas Mc Guire (1):
x86/asm: Fix typo in arch/x86/kernel/asm_offset_64.c
Rasmus Villemoes (1):
x86: Replace seq_printf() with seq_puts()
arch/x86/include/asm/mmu_context.h | 11 ++++++++++-
arch/x86/include/asm/switch_to.h | 12 ++++++++----
arch/x86/kernel/asm-offsets_64.c | 1 -
arch/x86/kernel/cpu/proc.c | 10 +++++-----
arch/x86/kernel/irq.c | 30 +++++++++++++++---------------
arch/x86/mm/pat.c | 2 +-
arch/x86/platform/uv/tlb_uv.c | 26 ++++++++++++--------------
7 files changed, 51 insertions(+), 41 deletions(-)
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 166af2a8e865..04478103df37 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -53,7 +53,16 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
/* Stop flush ipis for the previous mm */
cpumask_clear_cpu(cpu, mm_cpumask(prev));
- /* Load the LDT, if the LDT is different: */
+ /*
+ * Load the LDT, if the LDT is different.
+ *
+ * It's possible leave_mm(prev) has been called. If so,
+ * then prev->context.ldt could be out of sync with the
+ * LDT descriptor or the LDT register. This can only happen
+ * if prev->context.ldt is non-null, since we never free
+ * an LDT. But LDTs can't be shared across mms, so
+ * prev->context.ldt won't be equal to next->context.ldt.
+ */
if (unlikely(prev->context.ldt != next->context.ldt))
load_LDT_nolock(&next->context);
}
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h
index d7f3b3b78ac3..751bf4b7bf11 100644
--- a/arch/x86/include/asm/switch_to.h
+++ b/arch/x86/include/asm/switch_to.h
@@ -79,12 +79,12 @@ do { \
#else /* CONFIG_X86_32 */
/* frame pointer must be last for get_wchan */
-#define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
-#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t"
+#define SAVE_CONTEXT "pushq %%rbp ; movq %%rsi,%%rbp\n\t"
+#define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp\t"
#define __EXTRA_CLOBBER \
, "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \
- "r12", "r13", "r14", "r15"
+ "r12", "r13", "r14", "r15", "flags"
#ifdef CONFIG_CC_STACKPROTECTOR
#define __switch_canary \
@@ -100,7 +100,11 @@ do { \
#define __switch_canary_iparam
#endif /* CC_STACKPROTECTOR */
-/* Save restore flags to clear handle leaking NT */
+/*
+ * There is no need to save or restore flags, because flags are always
+ * clean in kernel mode, with the possible exception of IOPL. Kernel IOPL
+ * has no effect.
+ */
#define switch_to(prev, next, last) \
asm volatile(SAVE_CONTEXT \
"movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \
diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index e7c798b354fa..4f9359f36bb7 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -48,7 +48,6 @@ int main(void)
#define ENTRY(entry) OFFSET(pt_regs_ ## entry, pt_regs, entry)
ENTRY(bx);
- ENTRY(bx);
ENTRY(cx);
ENTRY(dx);
ENTRY(sp);
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 5433658e598d..e7d8c7608471 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -72,7 +72,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
if (c->x86_mask || c->cpuid_level >= 0)
seq_printf(m, "stepping\t: %d\n", c->x86_mask);
else
- seq_printf(m, "stepping\t: unknown\n");
+ seq_puts(m, "stepping\t: unknown\n");
if (c->microcode)
seq_printf(m, "microcode\t: 0x%x\n", c->microcode);
@@ -92,12 +92,12 @@ static int show_cpuinfo(struct seq_file *m, void *v)
show_cpuinfo_core(m, c, cpu);
show_cpuinfo_misc(m, c);
- seq_printf(m, "flags\t\t:");
+ seq_puts(m, "flags\t\t:");
for (i = 0; i < 32*NCAPINTS; i++)
if (cpu_has(c, i) && x86_cap_flags[i] != NULL)
seq_printf(m, " %s", x86_cap_flags[i]);
- seq_printf(m, "\nbugs\t\t:");
+ seq_puts(m, "\nbugs\t\t:");
for (i = 0; i < 32*NBUGINTS; i++) {
unsigned int bug_bit = 32*NCAPINTS + i;
@@ -118,7 +118,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
seq_printf(m, "address sizes\t: %u bits physical, %u bits virtual\n",
c->x86_phys_bits, c->x86_virt_bits);
- seq_printf(m, "power management:");
+ seq_puts(m, "power management:");
for (i = 0; i < 32; i++) {
if (c->x86_power & (1 << i)) {
if (i < ARRAY_SIZE(x86_power_flags) &&
@@ -131,7 +131,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
}
}
- seq_printf(m, "\n\n");
+ seq_puts(m, "\n\n");
return 0;
}
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 922d28581024..6307a0f0cf17 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -59,78 +59,78 @@ int arch_show_interrupts(struct seq_file *p, int prec)
seq_printf(p, "%*s: ", prec, "NMI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->__nmi_count);
- seq_printf(p, " Non-maskable interrupts\n");
+ seq_puts(p, " Non-maskable interrupts\n");
#ifdef CONFIG_X86_LOCAL_APIC
seq_printf(p, "%*s: ", prec, "LOC");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_timer_irqs);
- seq_printf(p, " Local timer interrupts\n");
+ seq_puts(p, " Local timer interrupts\n");
seq_printf(p, "%*s: ", prec, "SPU");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_spurious_count);
- seq_printf(p, " Spurious interrupts\n");
+ seq_puts(p, " Spurious interrupts\n");
seq_printf(p, "%*s: ", prec, "PMI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_perf_irqs);
- seq_printf(p, " Performance monitoring interrupts\n");
+ seq_puts(p, " Performance monitoring interrupts\n");
seq_printf(p, "%*s: ", prec, "IWI");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->apic_irq_work_irqs);
- seq_printf(p, " IRQ work interrupts\n");
+ seq_puts(p, " IRQ work interrupts\n");
seq_printf(p, "%*s: ", prec, "RTR");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->icr_read_retry_count);
- seq_printf(p, " APIC ICR read retries\n");
+ seq_puts(p, " APIC ICR read retries\n");
#endif
if (x86_platform_ipi_callback) {
seq_printf(p, "%*s: ", prec, "PLT");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
- seq_printf(p, " Platform interrupts\n");
+ seq_puts(p, " Platform interrupts\n");
}
#ifdef CONFIG_SMP
seq_printf(p, "%*s: ", prec, "RES");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
- seq_printf(p, " Rescheduling interrupts\n");
+ seq_puts(p, " Rescheduling interrupts\n");
seq_printf(p, "%*s: ", prec, "CAL");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_call_count -
irq_stats(j)->irq_tlb_count);
- seq_printf(p, " Function call interrupts\n");
+ seq_puts(p, " Function call interrupts\n");
seq_printf(p, "%*s: ", prec, "TLB");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
- seq_printf(p, " TLB shootdowns\n");
+ seq_puts(p, " TLB shootdowns\n");
#endif
#ifdef CONFIG_X86_THERMAL_VECTOR
seq_printf(p, "%*s: ", prec, "TRM");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
- seq_printf(p, " Thermal event interrupts\n");
+ seq_puts(p, " Thermal event interrupts\n");
#endif
#ifdef CONFIG_X86_MCE_THRESHOLD
seq_printf(p, "%*s: ", prec, "THR");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
- seq_printf(p, " Threshold APIC interrupts\n");
+ seq_puts(p, " Threshold APIC interrupts\n");
#endif
#ifdef CONFIG_X86_MCE
seq_printf(p, "%*s: ", prec, "MCE");
for_each_online_cpu(j)
seq_printf(p, "%10u ", per_cpu(mce_exception_count, j));
- seq_printf(p, " Machine check exceptions\n");
+ seq_puts(p, " Machine check exceptions\n");
seq_printf(p, "%*s: ", prec, "MCP");
for_each_online_cpu(j)
seq_printf(p, "%10u ", per_cpu(mce_poll_count, j));
- seq_printf(p, " Machine check polls\n");
+ seq_puts(p, " Machine check polls\n");
#endif
#if IS_ENABLED(CONFIG_HYPERV) || defined(CONFIG_XEN)
seq_printf(p, "%*s: ", prec, "THR");
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->irq_hv_callback_count);
- seq_printf(p, " Hypervisor callback interrupts\n");
+ seq_puts(p, " Hypervisor callback interrupts\n");
#endif
seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
#if defined(CONFIG_X86_IO_APIC)
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 657438858e83..c7eddbe6a612 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -824,7 +824,7 @@ static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
{
if (*pos == 0) {
++*pos;
- seq_printf(seq, "PAT memtype list:\n");
+ seq_puts(seq, "PAT memtype list:\n");
}
return memtype_get_idx(*pos);
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index 3968d67d366b..ab4062c5953c 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1367,20 +1367,18 @@ static int ptc_seq_show(struct seq_file *file, void *data)
cpu = *(loff_t *)data;
if (!cpu) {
- seq_printf(file,
- "# cpu bauoff sent stime self locals remotes ncpus localhub ");
- seq_printf(file,
- "remotehub numuvhubs numuvhubs16 numuvhubs8 ");
- seq_printf(file,
- "numuvhubs4 numuvhubs2 numuvhubs1 dto snacks retries ");
- seq_printf(file,
- "rok resetp resett giveup sto bz throt disable ");
- seq_printf(file,
- "enable wars warshw warwaits enters ipidis plugged ");
- seq_printf(file,
- "ipiover glim cong swack recv rtime all one mult ");
- seq_printf(file,
- "none retry canc nocan reset rcan\n");
+ seq_puts(file,
+ "# cpu bauoff sent stime self locals remotes ncpus localhub ");
+ seq_puts(file, "remotehub numuvhubs numuvhubs16 numuvhubs8 ");
+ seq_puts(file,
+ "numuvhubs4 numuvhubs2 numuvhubs1 dto snacks retries ");
+ seq_puts(file,
+ "rok resetp resett giveup sto bz throt disable ");
+ seq_puts(file,
+ "enable wars warshw warwaits enters ipidis plugged ");
+ seq_puts(file,
+ "ipiover glim cong swack recv rtime all one mult ");
+ seq_puts(file, "none retry canc nocan reset rcan\n");
}
if (cpu < num_possible_cpus() && cpu_online(cpu)) {
bcp = &per_cpu(bau_control, cpu);
--
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