From f1b7d45d3f8f3e18e190e71cb54d4b1917300d1d Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 19 May 2021 14:21:49 -0700 Subject: [PATCH 1/5] x86/irq: Remove unused vectors defines UV_BAU_MESSAGE is defined but not used anywhere in the kernel. Presumably this is a stale vector number that can be reclaimed. MCE_VECTOR is not an actual vector: #MC is an exception, not an interrupt vector, and as such is correctly described as X86_TRAP_MC. MCE_VECTOR is not used anywhere is the kernel. Note that NMI_VECTOR *is* used; specifically it is the vector number programmed into the APIC LVT when an NMI interrupt is configured. At the moment it is always numerically identical to X86_TRAP_NMI, that is not necessarily going to be the case indefinitely. Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Thomas Gleixner Acked-by: Steve Wahl Link: https://lore.kernel.org/r/20210519212154.511983-4-hpa@zytor.com --- arch/x86/include/asm/irq_vectors.h | 4 ++-- tools/arch/x86/include/asm/irq_vectors.h | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h index 889f8b1b5b7f..dc71b781be42 100644 --- a/arch/x86/include/asm/irq_vectors.h +++ b/arch/x86/include/asm/irq_vectors.h @@ -26,8 +26,8 @@ * This file enumerates the exact layout of them: */ +/* This is used as an interrupt vector when programming the APIC. */ #define NMI_VECTOR 0x02 -#define MCE_VECTOR 0x12 /* * IDT vectors usable for external interrupt sources start at 0x20. @@ -84,7 +84,7 @@ */ #define IRQ_WORK_VECTOR 0xf6 -#define UV_BAU_MESSAGE 0xf5 +/* 0xf5 - unused, was UV_BAU_MESSAGE */ #define DEFERRED_ERROR_VECTOR 0xf4 /* Vector on which hypervisor callbacks will be delivered */ diff --git a/tools/arch/x86/include/asm/irq_vectors.h b/tools/arch/x86/include/asm/irq_vectors.h index 889f8b1b5b7f..dc71b781be42 100644 --- a/tools/arch/x86/include/asm/irq_vectors.h +++ b/tools/arch/x86/include/asm/irq_vectors.h @@ -26,8 +26,8 @@ * This file enumerates the exact layout of them: */ +/* This is used as an interrupt vector when programming the APIC. */ #define NMI_VECTOR 0x02 -#define MCE_VECTOR 0x12 /* * IDT vectors usable for external interrupt sources start at 0x20. @@ -84,7 +84,7 @@ */ #define IRQ_WORK_VECTOR 0xf6 -#define UV_BAU_MESSAGE 0xf5 +/* 0xf5 - unused, was UV_BAU_MESSAGE */ #define DEFERRED_ERROR_VECTOR 0xf4 /* Vector on which hypervisor callbacks will be delivered */ From ff851003880de9d1111498877551ba16668c38ef Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 19 May 2021 14:21:48 -0700 Subject: [PATCH 2/5] x86/irq: Add and use NR_EXTERNAL_VECTORS and NR_SYSTEM_VECTORS Add defines for the number of external vectors and number of system vectors instead of requiring the use of (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) and (NR_VECTORS - FIRST_SYSTEM_VECTOR) respectively. Clean up the usage sites. Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Thomas Gleixner Acked-by: Andy Lutomirski Link: https://lore.kernel.org/r/20210519212154.511983-3-hpa@zytor.com --- arch/x86/include/asm/idtentry.h | 4 ++-- arch/x86/include/asm/irq_vectors.h | 3 +++ tools/arch/x86/include/asm/irq_vectors.h | 3 +++ 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 73d45b0dfff2..c03a18cac78e 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -504,7 +504,7 @@ __visible noinstr void func(struct pt_regs *regs, \ .align 8 SYM_CODE_START(irq_entries_start) vector=FIRST_EXTERNAL_VECTOR - .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) + .rept NR_EXTERNAL_VECTORS UNWIND_HINT_IRET_REGS 0 : .byte 0x6a, vector @@ -520,7 +520,7 @@ SYM_CODE_END(irq_entries_start) .align 8 SYM_CODE_START(spurious_entries_start) vector=FIRST_SYSTEM_VECTOR - .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR) + .rept NR_SYSTEM_VECTORS UNWIND_HINT_IRET_REGS 0 : .byte 0x6a, vector diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h index dc71b781be42..43dcb9284208 100644 --- a/arch/x86/include/asm/irq_vectors.h +++ b/arch/x86/include/asm/irq_vectors.h @@ -114,6 +114,9 @@ #define FIRST_SYSTEM_VECTOR NR_VECTORS #endif +#define NR_EXTERNAL_VECTORS (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) +#define NR_SYSTEM_VECTORS (NR_VECTORS - FIRST_SYSTEM_VECTOR) + /* * Size the maximum number of interrupts. * diff --git a/tools/arch/x86/include/asm/irq_vectors.h b/tools/arch/x86/include/asm/irq_vectors.h index dc71b781be42..43dcb9284208 100644 --- a/tools/arch/x86/include/asm/irq_vectors.h +++ b/tools/arch/x86/include/asm/irq_vectors.h @@ -114,6 +114,9 @@ #define FIRST_SYSTEM_VECTOR NR_VECTORS #endif +#define NR_EXTERNAL_VECTORS (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) +#define NR_SYSTEM_VECTORS (NR_VECTORS - FIRST_SYSTEM_VECTOR) + /* * Size the maximum number of interrupts. * From 8ec9069a432c873e52e6f4ce1496f282a4299604 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 19 May 2021 14:21:50 -0700 Subject: [PATCH 3/5] x86/idt: Remove address argument from idt_invalidate() There is no reason to specify any specific address to idt_invalidate(). It looks mostly like an artifact of unifying code done differently by accident. The most "sensible" address to set here is a NULL pointer - virtual address zero, just as a visual marker. This also makes it possible to mark the struct desc_ptr in idt_invalidate() as static const. Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210519212154.511983-5-hpa@zytor.com --- arch/x86/include/asm/desc.h | 2 +- arch/x86/kernel/idt.c | 5 ++--- arch/x86/kernel/machine_kexec_32.c | 2 +- arch/x86/kernel/reboot.c | 2 +- 4 files changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 476082a83d1c..b8429ae50b71 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -427,6 +427,6 @@ static inline void idt_setup_early_pf(void) { } static inline void idt_setup_ist_traps(void) { } #endif -extern void idt_invalidate(void *addr); +extern void idt_invalidate(void); #endif /* _ASM_X86_DESC_H */ diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index d552f177eca0..2779f5226dc2 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -331,11 +331,10 @@ void __init idt_setup_early_handler(void) /** * idt_invalidate - Invalidate interrupt descriptor table - * @addr: The virtual address of the 'invalid' IDT */ -void idt_invalidate(void *addr) +void idt_invalidate(void) { - struct desc_ptr idt = { .address = (unsigned long) addr, .size = 0 }; + static const struct desc_ptr idt = { .address = 0, .size = 0 }; load_idt(&idt); } diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c index 64b00b0d7fe8..1e34feebcd5d 100644 --- a/arch/x86/kernel/machine_kexec_32.c +++ b/arch/x86/kernel/machine_kexec_32.c @@ -232,7 +232,7 @@ void machine_kexec(struct kimage *image) * The gdt & idt are now invalid. * If you want to load them you must set up your own idt & gdt. */ - idt_invalidate(phys_to_virt(0)); + idt_invalidate(); set_gdt(phys_to_virt(0), 0); /* now call it */ diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index b29657b76e3f..ebfb91108232 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -669,7 +669,7 @@ static void native_machine_emergency_restart(void) break; case BOOT_TRIPLE: - idt_invalidate(NULL); + idt_invalidate(); __asm__ __volatile__("int3"); /* We're probably dead after this, but... */ From 283fa3b6483a84aeb62f1b97c2ec7c02eb2f5882 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 19 May 2021 14:21:51 -0700 Subject: [PATCH 4/5] x86: Add native_[ig]dt_invalidate() In some places, the native forms of descriptor table invalidation is required. Rather than open-coding them, add explicitly native functions to invalidate the GDT and IDT. Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210519212154.511983-6-hpa@zytor.com --- arch/x86/include/asm/desc.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index b8429ae50b71..400c17862870 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -224,6 +224,26 @@ static inline void store_idt(struct desc_ptr *dtr) asm volatile("sidt %0":"=m" (*dtr)); } +static inline void native_gdt_invalidate(void) +{ + const struct desc_ptr invalid_gdt = { + .address = 0, + .size = 0 + }; + + native_load_gdt(&invalid_gdt); +} + +static inline void native_idt_invalidate(void) +{ + const struct desc_ptr invalid_idt = { + .address = 0, + .size = 0 + }; + + native_load_idt(&invalid_idt); +} + /* * The LTR instruction marks the TSS GDT entry as busy. On 64-bit, the GDT is * a read-only remapping. To prevent a page fault, the GDT is switched to the From 056c52f5e824c050c58fd27ea6d717cba32239c2 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 19 May 2021 14:21:52 -0700 Subject: [PATCH 5/5] x86/kexec: Set_[gi]dt() -> native_[gi]dt_invalidate() in machine_kexec_*.c These files contain private set_gdt() functions which are only used to invalid the gdt; machine_kexec_64.c also contains a set_idt() function to invalidate the idt. phys_to_virt(0) *really* doesn't make any sense for creating an invalid GDT. A NULL pointer (virtual 0) makes a lot more sense; although neither will allow any actual memory reference, a NULL pointer stands out more. Replace these calls with native_[gi]dt_invalidate(). Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210519212154.511983-7-hpa@zytor.com --- arch/x86/kernel/machine_kexec_32.c | 15 ++------------ arch/x86/kernel/machine_kexec_64.c | 33 ++---------------------------- 2 files changed, 4 insertions(+), 44 deletions(-) diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c index 1e34feebcd5d..1b373d79cedc 100644 --- a/arch/x86/kernel/machine_kexec_32.c +++ b/arch/x86/kernel/machine_kexec_32.c @@ -23,17 +23,6 @@ #include #include -static void set_gdt(void *newgdt, __u16 limit) -{ - struct desc_ptr curgdt; - - /* ia32 supports unaligned loads & stores */ - curgdt.size = limit; - curgdt.address = (unsigned long)newgdt; - - load_gdt(&curgdt); -} - static void load_segments(void) { #define __STR(X) #X @@ -232,8 +221,8 @@ void machine_kexec(struct kimage *image) * The gdt & idt are now invalid. * If you want to load them you must set up your own idt & gdt. */ - idt_invalidate(); - set_gdt(phys_to_virt(0), 0); + native_idt_invalidate(); + native_gdt_invalidate(); /* now call it */ image->start = relocate_kernel_ptr((unsigned long)image->head, diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index c078b0d3ab0e..131f30fdcfbd 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -256,35 +256,6 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable) return init_transition_pgtable(image, level4p); } -static void set_idt(void *newidt, u16 limit) -{ - struct desc_ptr curidt; - - /* x86-64 supports unaligned loads & stores */ - curidt.size = limit; - curidt.address = (unsigned long)newidt; - - __asm__ __volatile__ ( - "lidtq %0\n" - : : "m" (curidt) - ); -}; - - -static void set_gdt(void *newgdt, u16 limit) -{ - struct desc_ptr curgdt; - - /* x86-64 supports unaligned loads & stores */ - curgdt.size = limit; - curgdt.address = (unsigned long)newgdt; - - __asm__ __volatile__ ( - "lgdtq %0\n" - : : "m" (curgdt) - ); -}; - static void load_segments(void) { __asm__ __volatile__ ( @@ -379,8 +350,8 @@ void machine_kexec(struct kimage *image) * The gdt & idt are now invalid. * If you want to load them you must set up your own idt & gdt. */ - set_gdt(phys_to_virt(0), 0); - set_idt(phys_to_virt(0), 0); + native_idt_invalidate(); + native_gdt_invalidate(); /* now call it */ image->start = relocate_kernel((unsigned long)image->head,