From 718f5d0030da8669404dab873336b16c169b430b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 28 Aug 2017 08:47:39 +0200 Subject: x86/fpu: Use bitfield accessors for desc_struct desc_struct is a union of u32 fields and bitfields. The access to the u32 fields is done with magic macros. Convert it to use the bitfields and replace the macro magic with parseable inline functions. Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20170828064958.042406718@linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/math-emu/fpu_entry.c | 11 +++++----- arch/x86/math-emu/fpu_system.h | 48 +++++++++++++++++++++++++++++++---------- arch/x86/math-emu/get_address.c | 17 ++++++++------- 3 files changed, 51 insertions(+), 25 deletions(-) (limited to 'arch/x86/math-emu') diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index 0203baefb5c0..d4a7df2205b8 100644 --- a/arch/x86/math-emu/fpu_entry.c +++ b/arch/x86/math-emu/fpu_entry.c @@ -147,7 +147,7 @@ void math_emulate(struct math_emu_info *info) } code_descriptor = FPU_get_ldt_descriptor(FPU_CS); - if (SEG_D_SIZE(code_descriptor)) { + if (code_descriptor.d) { /* The above test may be wrong, the book is not clear */ /* Segmented 32 bit protected mode */ addr_modes.default_mode = SEG32; @@ -155,11 +155,10 @@ void math_emulate(struct math_emu_info *info) /* 16 bit protected mode */ addr_modes.default_mode = PM16; } - FPU_EIP += code_base = SEG_BASE_ADDR(code_descriptor); - code_limit = code_base - + (SEG_LIMIT(code_descriptor) + - 1) * SEG_GRANULARITY(code_descriptor) - - 1; + FPU_EIP += code_base = seg_get_base(&code_descriptor); + code_limit = seg_get_limit(&code_descriptor) + 1; + code_limit *= seg_get_granularity(&code_descriptor); + code_limit += code_base - 1; if (code_limit < code_base) code_limit = 0xffffffff; } diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h index a179254a5122..2319a257ec32 100644 --- a/arch/x86/math-emu/fpu_system.h +++ b/arch/x86/math-emu/fpu_system.h @@ -34,17 +34,43 @@ static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg) return ret; } -#define SEG_D_SIZE(x) ((x).b & (3 << 21)) -#define SEG_G_BIT(x) ((x).b & (1 << 23)) -#define SEG_GRANULARITY(x) (((x).b & (1 << 23)) ? 4096 : 1) -#define SEG_286_MODE(x) ((x).b & ( 0xff000000 | 0xf0000 | (1 << 23))) -#define SEG_BASE_ADDR(s) (((s).b & 0xff000000) \ - | (((s).b & 0xff) << 16) | ((s).a >> 16)) -#define SEG_LIMIT(s) (((s).b & 0xff0000) | ((s).a & 0xffff)) -#define SEG_EXECUTE_ONLY(s) (((s).b & ((1 << 11) | (1 << 9))) == (1 << 11)) -#define SEG_WRITE_PERM(s) (((s).b & ((1 << 11) | (1 << 9))) == (1 << 9)) -#define SEG_EXPAND_DOWN(s) (((s).b & ((1 << 11) | (1 << 10))) \ - == (1 << 10)) +#define SEG_TYPE_WRITABLE (1U << 1) +#define SEG_TYPE_EXPANDS_DOWN (1U << 2) +#define SEG_TYPE_EXECUTE (1U << 3) +#define SEG_TYPE_EXPAND_MASK (SEG_TYPE_EXPANDS_DOWN | SEG_TYPE_EXECUTE) +#define SEG_TYPE_EXECUTE_MASK (SEG_TYPE_WRITABLE | SEG_TYPE_EXECUTE) + +static inline unsigned long seg_get_base(struct desc_struct *d) +{ + unsigned long base = (unsigned long)d->base2 << 24; + + return base | ((unsigned long)d->base1 << 16) | d->base0; +} + +static inline unsigned long seg_get_limit(struct desc_struct *d) +{ + return ((unsigned long)d->limit << 16) | d->limit0; +} + +static inline unsigned long seg_get_granularity(struct desc_struct *d) +{ + return d->g ? 4096 : 1; +} + +static inline bool seg_expands_down(struct desc_struct *d) +{ + return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN; +} + +static inline bool seg_execute_only(struct desc_struct *d) +{ + return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE; +} + +static inline bool seg_writable(struct desc_struct *d) +{ + return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE; +} #define I387 (¤t->thread.fpu.state) #define FPU_info (I387->soft.info) diff --git a/arch/x86/math-emu/get_address.c b/arch/x86/math-emu/get_address.c index b8ef9f9d2ffc..c48967c6a0e2 100644 --- a/arch/x86/math-emu/get_address.c +++ b/arch/x86/math-emu/get_address.c @@ -159,17 +159,18 @@ static long pm_address(u_char FPU_modrm, u_char segment, } descriptor = FPU_get_ldt_descriptor(addr->selector); - base_address = SEG_BASE_ADDR(descriptor); + base_address = seg_get_base(&descriptor); address = base_address + offset; - limit = base_address - + (SEG_LIMIT(descriptor) + 1) * SEG_GRANULARITY(descriptor) - 1; + limit = seg_get_limit(&descriptor) + 1; + limit *= seg_get_granularity(&descriptor); + limit += base_address - 1; if (limit < base_address) limit = 0xffffffff; - if (SEG_EXPAND_DOWN(descriptor)) { - if (SEG_G_BIT(descriptor)) + if (seg_expands_down(&descriptor)) { + if (descriptor.g) { seg_top = 0xffffffff; - else { + } else { seg_top = base_address + (1 << 20); if (seg_top < base_address) seg_top = 0xffffffff; @@ -182,8 +183,8 @@ static long pm_address(u_char FPU_modrm, u_char segment, (address > limit) || (address < base_address) ? 0 : ((limit - address) >= 254 ? 255 : limit - address + 1); } - if (SEG_EXECUTE_ONLY(descriptor) || - (!SEG_WRITE_PERM(descriptor) && (FPU_modrm & FPU_WRITE_BIT))) { + if (seg_execute_only(&descriptor) || + (!seg_writable(&descriptor) && (FPU_modrm & FPU_WRITE_BIT))) { access_limit = 0; } return address; -- cgit v1.2.3 From 38e9e81f4c81c75799b002d5811de7241b307676 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 28 Aug 2017 08:47:41 +0200 Subject: x86/gdt: Use bitfields for initialization The GDT entry related code uses two ways to access entries via union fields: - bitfields - macros which initialize the two 16-bit parts of the entry by magic shift and mask operations. Clean it up and only use the bitfields to initialize and access entries. ( The old access patterns were partly done due to GCC optimizing bitfield accesses in a horrible way - that's mostly fixed these days and clarity of code in such low level accessors is very important. ) Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20170828064958.197673367@linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/entry/vdso/vma.c | 2 +- arch/x86/include/asm/desc.h | 26 +++++++++++++++--------- arch/x86/include/asm/desc_defs.h | 44 ++++++++++++++++++---------------------- arch/x86/math-emu/fpu_system.h | 2 +- 4 files changed, 38 insertions(+), 36 deletions(-) (limited to 'arch/x86/math-emu') diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index 726355ce8497..1911310959f8 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -351,7 +351,7 @@ static void vgetcpu_cpu_init(void *arg) * and 8 bits for the node) */ d.limit0 = cpu | ((node & 0xf) << 12); - d.limit = node >> 4; + d.limit1 = node >> 4; d.type = 5; /* RO data, expand down, accessed */ d.dpl = 3; /* Visible to user code */ d.s = 1; /* Not a system segment */ diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 0731064c633b..2090cd223505 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -23,7 +23,7 @@ static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *in desc->s = 1; desc->dpl = 0x3; desc->p = info->seg_not_present ^ 1; - desc->limit = (info->limit & 0xf0000) >> 16; + desc->limit1 = (info->limit & 0xf0000) >> 16; desc->avl = info->useable; desc->d = info->seg_32bit; desc->g = info->limit_in_pages; @@ -170,14 +170,20 @@ static inline void pack_descriptor(struct desc_struct *desc, unsigned long base, unsigned long limit, unsigned char type, unsigned char flags) { - desc->a = ((base & 0xffff) << 16) | (limit & 0xffff); - desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) | - (limit & 0x000f0000) | ((type & 0xff) << 8) | - ((flags & 0xf) << 20); - desc->p = 1; + desc->limit0 = (u16) limit; + desc->base0 = (u16) base; + desc->base1 = (base >> 16) & 0xFF; + desc->type = type & 0x0F; + desc->s = 0; + desc->dpl = 0; + desc->p = 1; + desc->limit1 = (limit >> 16) & 0xF; + desc->avl = (flags >> 0) & 0x01; + desc->l = (flags >> 1) & 0x01; + desc->d = (flags >> 2) & 0x01; + desc->g = (flags >> 3) & 0x01; } - static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned type, unsigned size) { @@ -195,7 +201,7 @@ static inline void set_tssldt_descriptor(void *d, unsigned long addr, desc->base2 = (addr >> 24) & 0xFF; desc->base3 = (u32) (addr >> 32); #else - pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0); + pack_descriptor((struct desc_struct *)d, addr, size, type, 0); #endif } @@ -395,13 +401,13 @@ static inline void set_desc_base(struct desc_struct *desc, unsigned long base) static inline unsigned long get_desc_limit(const struct desc_struct *desc) { - return desc->limit0 | (desc->limit << 16); + return desc->limit0 | (desc->limit1 << 16); } static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit) { desc->limit0 = limit & 0xffff; - desc->limit = (limit >> 16) & 0xf; + desc->limit1 = (limit >> 16) & 0xf; } #ifdef CONFIG_X86_64 diff --git a/arch/x86/include/asm/desc_defs.h b/arch/x86/include/asm/desc_defs.h index d684bee8a59a..1b9494e006a1 100644 --- a/arch/x86/include/asm/desc_defs.h +++ b/arch/x86/include/asm/desc_defs.h @@ -11,34 +11,30 @@ #include -/* - * FIXME: Accessing the desc_struct through its fields is more elegant, - * and should be the one valid thing to do. However, a lot of open code - * still touches the a and b accessors, and doing this allow us to do it - * incrementally. We keep the signature as a struct, rather than a union, - * so we can get rid of it transparently in the future -- glommer - */ /* 8 byte segment descriptor */ struct desc_struct { - union { - struct { - unsigned int a; - unsigned int b; - }; - struct { - u16 limit0; - u16 base0; - unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1; - unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8; - }; - }; + u16 limit0; + u16 base0; + u16 base1: 8, type: 4, s: 1, dpl: 2, p: 1; + u16 limit1: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8; } __attribute__((packed)); -#define GDT_ENTRY_INIT(flags, base, limit) { { { \ - .a = ((limit) & 0xffff) | (((base) & 0xffff) << 16), \ - .b = (((base) & 0xff0000) >> 16) | (((flags) & 0xf0ff) << 8) | \ - ((limit) & 0xf0000) | ((base) & 0xff000000), \ - } } } +#define GDT_ENTRY_INIT(flags, base, limit) \ + { \ + .limit0 = (u16) (limit), \ + .limit1 = ((limit) >> 16) & 0x0F, \ + .base0 = (u16) (base), \ + .base1 = ((base) >> 16) & 0xFF, \ + .base2 = ((base) >> 24) & 0xFF, \ + .type = (flags & 0x0f), \ + .s = (flags >> 4) & 0x01, \ + .dpl = (flags >> 5) & 0x03, \ + .p = (flags >> 7) & 0x01, \ + .avl = (flags >> 12) & 0x01, \ + .l = (flags >> 13) & 0x01, \ + .d = (flags >> 14) & 0x01, \ + .g = (flags >> 15) & 0x01, \ + } enum { GATE_INTERRUPT = 0xE, diff --git a/arch/x86/math-emu/fpu_system.h b/arch/x86/math-emu/fpu_system.h index 2319a257ec32..699f329f1d40 100644 --- a/arch/x86/math-emu/fpu_system.h +++ b/arch/x86/math-emu/fpu_system.h @@ -49,7 +49,7 @@ static inline unsigned long seg_get_base(struct desc_struct *d) static inline unsigned long seg_get_limit(struct desc_struct *d) { - return ((unsigned long)d->limit << 16) | d->limit0; + return ((unsigned long)d->limit1 << 16) | d->limit0; } static inline unsigned long seg_get_granularity(struct desc_struct *d) -- cgit v1.2.3