[tip:x86/apic] x86/idt: Unify gate_struct handling for 32/64-bit kernels

tip-bot for Thomas Gleixner
2017-08-29T11:18:42Z

Commit-ID: 64b163fab684e3de47aa8db6cc08ae7d2e194373
Gitweb: http://git.kernel.org/tip/64b163fab684e3de47aa8db6cc08ae7d2e194373
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:37 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 29 Aug 2017 12:07:24 +0200

x86/idt: Unify gate_struct handling for 32/64-bit kernels

The first 32 bits of gate struct are the same for 32 and 64 bit kernels.

The 32-bit version uses desc_struct and no designated data structure,
so we need different accessors for 32 and 64 bit kernels.

Aside of that the macros which are necessary to build the 32-bit
gate descriptor are horrible to read.

Unify the gate structs and switch all code fiddling with it over.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064957.861974317@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/boot/compressed/eboot.c | 8 +++---
arch/x86/include/asm/desc.h | 45 ++++++++++++++-----------------
arch/x86/include/asm/desc_defs.h | 57 ++++++++++++++++++++++++++--------------
arch/x86/kvm/vmx.c | 2 +-
arch/x86/xen/enlighten_pv.c | 12 ++++-----
5 files changed, 67 insertions(+), 57 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index c3e869e..65f0b24 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -1058,7 +1058,7 @@ struct boot_params *efi_main(struct efi_config *c,
desc->s = DESC_TYPE_CODE_DATA;
desc->dpl = 0;
desc->p = 1;
- desc->limit = 0xf;
+ desc->limit1 = 0xf;
desc->avl = 0;
desc->l = 0;
desc->d = SEG_OP_SIZE_32BIT;
@@ -1078,7 +1078,7 @@ struct boot_params *efi_main(struct efi_config *c,
desc->s = DESC_TYPE_CODE_DATA;
desc->dpl = 0;
desc->p = 1;
- desc->limit = 0xf;
+ desc->limit1 = 0xf;
desc->avl = 0;
if (IS_ENABLED(CONFIG_X86_64)) {
desc->l = 1;
@@ -1099,7 +1099,7 @@ struct boot_params *efi_main(struct efi_config *c,
desc->s = DESC_TYPE_CODE_DATA;
desc->dpl = 0;
desc->p = 1;
- desc->limit = 0xf;
+ desc->limit1 = 0xf;
desc->avl = 0;
desc->l = 0;
desc->d = SEG_OP_SIZE_32BIT;
@@ -1116,7 +1116,7 @@ struct boot_params *efi_main(struct efi_config *c,
desc->s = 0;
desc->dpl = 0;
desc->p = 1;
- desc->limit = 0x0;
+ desc->limit1 = 0x0;
desc->avl = 0;
desc->l = 0;
desc->d = 0;
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index d18a604..0731064 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -84,33 +84,25 @@ static inline phys_addr_t get_cpu_gdt_paddr(unsigned int cpu)
return per_cpu_ptr_to_phys(get_cpu_gdt_rw(cpu));
}

-#ifdef CONFIG_X86_64
-
static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
unsigned dpl, unsigned ist, unsigned seg)
{
- gate->offset_low = PTR_LOW(func);
+ gate->offset_low = (u16) func;
+ gate->bits.p = 1;
+ gate->bits.dpl = dpl;
+ gate->bits.zero = 0;
+ gate->bits.type = type;
+ gate->offset_middle = (u16) (func >> 16);
+#ifdef CONFIG_X86_64
gate->segment = __KERNEL_CS;
- gate->ist = ist;
- gate->p = 1;
- gate->dpl = dpl;
- gate->zero0 = 0;
- gate->zero1 = 0;
- gate->type = type;
- gate->offset_middle = PTR_MIDDLE(func);
- gate->offset_high = PTR_HIGH(func);
-}
-
+ gate->bits.ist = ist;
+ gate->reserved = 0;
+ gate->offset_high = (u32) (func >> 32);
#else
-static inline void pack_gate(gate_desc *gate, unsigned char type,
- unsigned long base, unsigned dpl, unsigned flags,
- unsigned short seg)
-{
- gate->a = (seg << 16) | (base & 0xffff);
- gate->b = (base & 0xffff0000) | (((0x80 | type | (dpl << 5)) & 0xff) << 8);
-}
-
+ gate->segment = seg;
+ gate->bits.ist = 0;
#endif
+}

static inline int desc_empty(const void *ptr)
{
@@ -186,7 +178,8 @@ static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
}

-static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned type, unsigned size)
+static inline void set_tssldt_descriptor(void *d, unsigned long addr,
+ unsigned type, unsigned size)
{
#ifdef CONFIG_X86_64
struct ldttss_desc64 *desc = d;
@@ -194,13 +187,13 @@ static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned t
memset(desc, 0, sizeof(*desc));

desc->limit0 = size & 0xFFFF;
- desc->base0 = PTR_LOW(addr);
- desc->base1 = PTR_MIDDLE(addr) & 0xFF;
+ desc->base0 = (u16) addr;
+ desc->base1 = (addr >> 16) & 0xFF;
desc->type = type;
desc->p = 1;
desc->limit1 = (size >> 16) & 0xF;
- desc->base2 = (PTR_MIDDLE(addr) >> 8) & 0xFF;
- desc->base3 = PTR_HIGH(addr);
+ desc->base2 = (addr >> 24) & 0xFF;
+ desc->base3 = (u32) (addr >> 32);
#else
pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
#endif
diff --git a/arch/x86/include/asm/desc_defs.h b/arch/x86/include/asm/desc_defs.h
index 4926534..d684bee 100644
--- a/arch/x86/include/asm/desc_defs.h
+++ b/arch/x86/include/asm/desc_defs.h
@@ -47,20 +47,6 @@ enum {
GATE_TASK = 0x5,
};

-/* 16byte gate */
-struct gate_struct64 {
- u16 offset_low;
- u16 segment;
- unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
- u16 offset_middle;
- u32 offset_high;
- u32 zero1;
-} __attribute__((packed));
-
-#define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF)
-#define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF)
-#define PTR_HIGH(x) ((unsigned long long)(x) >> 32)
-
enum {
DESC_TSS = 0x9,
DESC_LDT = 0x2,
@@ -77,20 +63,51 @@ struct ldttss_desc64 {
u32 zero1;
} __attribute__((packed));

+
#ifdef CONFIG_X86_64
-typedef struct gate_struct64 gate_desc;
typedef struct ldttss_desc64 ldt_desc;
typedef struct ldttss_desc64 tss_desc;
-#define gate_offset(g) ((g).offset_low | ((unsigned long)(g).offset_middle << 16) | ((unsigned long)(g).offset_high << 32))
-#define gate_segment(g) ((g).segment)
#else
-typedef struct desc_struct gate_desc;
typedef struct desc_struct ldt_desc;
typedef struct desc_struct tss_desc;
-#define gate_offset(g) (((g).b & 0xffff0000) | ((g).a & 0x0000ffff))
-#define gate_segment(g) ((g).a >> 16)
#endif

+struct idt_bits {
+ u16 ist : 3,
+ zero : 5,
+ type : 5,
+ dpl : 2,
+ p : 1;
+} __attribute__((packed));
+
+struct gate_struct {
+ u16 offset_low;
+ u16 segment;
+ struct idt_bits bits;
+ u16 offset_middle;
+#ifdef CONFIG_X86_64
+ u32 offset_high;
+ u32 reserved;
+#endif
+} __attribute__((packed));
+
+typedef struct gate_struct gate_desc;
+
+static inline unsigned long gate_offset(const gate_desc *g)
+{
+#ifdef CONFIG_X86_64
+ return g->offset_low | ((unsigned long)g->offset_middle << 16) |
+ ((unsigned long) g->offset_high << 32);
+#else
+ return g->offset_low | ((unsigned long)g->offset_middle << 16);
+#endif
+}
+
+static inline unsigned long gate_segment(const gate_desc *g)
+{
+ return g->segment;
+}
+
struct desc_ptr {
unsigned short size;
unsigned long address;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c6ef294..08d00ee 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8779,7 +8779,7 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)

vector = exit_intr_info & INTR_INFO_VECTOR_MASK;
desc = (gate_desc *)vmx->host_idt_base + vector;
- entry = gate_offset(*desc);
+ entry = gate_offset(desc);
asm volatile(
#ifdef CONFIG_X86_64
"mov %%" _ASM_SP ", %[sp]\n\t"
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 9849152..4c5d72b 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -584,12 +584,12 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val,
{
unsigned long addr;

- if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
+ if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
return 0;

info->vector = vector;

- addr = gate_offset(*val);
+ addr = gate_offset(val);
#ifdef CONFIG_X86_64
/*
* Look for known traps using IST, and substitute them
@@ -622,16 +622,16 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val,
;
else {
/* Some other trap using IST? */
- if (WARN_ON(val->ist != 0))
+ if (WARN_ON(val->bits.ist != 0))
return 0;
}
#endif /* CONFIG_X86_64 */
info->address = addr;

- info->cs = gate_segment(*val);
- info->flags = val->dpl;
+ info->cs = gate_segment(val);
+ info->flags = val->bits.dpl;
/* interrupt gates clear IF */
- if (val->type == GATE_INTERRUPT)
+ if (val->bits.type == GATE_INTERRUPT)
info->flags |= 1 << 2;

return 1;