Messages in this thread Patch in this message | | | From | Borislav Petkov <> | Subject | [PATCH] x86/cpu: Init exception handling from cpu_init() | Date | Tue, 4 May 2021 19:17:45 +0200 |
| |
From: Borislav Petkov <bp@suse.de>
SEV-ES guests require properly setup task register with which the TSS descriptor in the GDT can be located so that the IST-type #VC exception handler which they need to function properly, can be executed.
This setup needs to happen before attempting to load microcode in ucode_cpu_init() which can cause such #VC exceptions.
Simplify the machinery by running that exception setup from cpu_init() directly.
There should be no functional changes resulting from this patch.
Signed-off-by: Borislav Petkov <bp@suse.de> --- arch/x86/include/asm/processor.h | 1 - arch/x86/kernel/cpu/common.c | 14 +++----------- arch/x86/kernel/smpboot.c | 1 - 3 files changed, 3 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 154321d29050..50059c988167 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -663,7 +663,6 @@ extern void load_direct_gdt(int); extern void load_fixmap_gdt(int); extern void load_percpu_segment(int); extern void cpu_init(void); -extern void cpu_init_exception_handling(void); extern void cr4_init(void); static inline unsigned long get_debugctlmsr(void) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 6bdb69a9a7dc..1aa20b5e4e66 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1917,7 +1917,7 @@ static inline void tss_setup_io_bitmap(struct tss_struct *tss) * Setup everything needed to handle exceptions from the IDT, including the IST * exceptions which use paranoid_entry(). */ -void cpu_init_exception_handling(void) +static void init_exception_handling(void) { struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); int cpu = raw_smp_processor_id(); @@ -1944,10 +1944,11 @@ void cpu_init_exception_handling(void) */ void cpu_init(void) { - struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw); struct task_struct *cur = current; int cpu = raw_smp_processor_id(); + init_exception_handling(); + wait_for_master_cpu(cpu); ucode_cpu_init(cpu); @@ -1957,8 +1958,6 @@ void cpu_init(void) early_cpu_to_node(cpu) != NUMA_NO_NODE) set_numa_node(early_cpu_to_node(cpu)); #endif - setup_getcpu(cpu); - pr_debug("Initializing CPU#%d\n", cpu); if (IS_ENABLED(CONFIG_X86_64) || cpu_feature_enabled(X86_FEATURE_VME) || @@ -1970,7 +1969,6 @@ void cpu_init(void) * and set up the GDT descriptor: */ switch_to_new_gdt(cpu); - load_current_idt(); if (IS_ENABLED(CONFIG_X86_64)) { loadsegment(fs, 0); @@ -1990,12 +1988,6 @@ void cpu_init(void) initialize_tlbstate_and_flush(); enter_lazy_tlb(&init_mm, cur); - /* Initialize the TSS. */ - tss_setup_ist(tss); - tss_setup_io_bitmap(tss); - set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); - - load_TR_desc(); /* * sp0 points to the entry trampoline stack regardless of what task * is running. diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 7ffb0cf3f997..5e5899d046e4 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -232,7 +232,6 @@ static void notrace start_secondary(void *unused) load_cr3(swapper_pg_dir); __flush_tlb_all(); #endif - cpu_init_exception_handling(); cpu_init(); rcu_cpu_starting(raw_smp_processor_id()); x86_cpuinit.early_percpu_clock_init(); -- 2.29.2
| |