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/math-emu/fpu_system.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/math-emu') 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