[patch V3 22/44] x86/idt: Unify gate_struct handling for 32/64bit

Thomas Gleixner
2017-08-28T06:58:59Z

[-- Attachment #1: x86-idt--Unify-gate_struct-handling-for-32-64bit.patch --]
[-- Type: text/plain, Size: 7337 bytes --]

The first 32bits of gate struct are the same for 32 and 64 bit. The 32bit
version uses desc_struct and no designated data structure, so we need
different accessors for 32 and 64 bit. Aside of that the macros which are
necessary to build the 32bit 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>
---
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(-)

--- 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_
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_
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_
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_
desc->s = 0;
desc->dpl = 0;
desc->p = 1;
- desc->limit = 0x0;
+ desc->limit1 = 0x0;
desc->avl = 0;
desc->l = 0;
desc->d = 0;
--- 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_pa
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(struc
}

-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
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
--- 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;
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8786,7 +8786,7 @@ static void vmx_handle_external_intr(str

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"
--- 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,
{
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,
;
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;