diff options
author | Paul Mackerras <paulus@samba.org> | 2007-08-10 14:07:38 +1000 |
---|---|---|
committer | Paul Mackerras <paulus@samba.org> | 2007-08-17 11:01:55 +1000 |
commit | c6d4267eced79775399f256fbb4adb671e9b597e (patch) | |
tree | 211acc4464342ba2d87365367c3afb4ce509038d /arch/powerpc/kernel/align.c | |
parent | 09a54101e15f43607722dee55f33d1962653c6cb (diff) | |
download | linux-c6d4267eced79775399f256fbb4adb671e9b597e.tar.bz2 |
[POWERPC] Handle alignment faults on new FP load/store instructions
This adds code to handle alignment traps generated by the following
new floating-point load/store instructions, by emulating the
instruction in the kernel (as is done for other instructions that
generate alignment traps):
lfiwax load floating-point as integer word algebraic indexed
stfiwx store floating-point as integer word indexed
lfdp load floating-point double pair
lfdpx load floating-point double pair indexed
stfdp store floating-point double pair
stfdpx store floating-point double pair indexed
All these except stfiwx are new in POWER6.
lfdp/lfdpx/stfdp/stfdpx load and store 16 bytes of memory into an
even/odd FP register pair. In little-endian mode each 8-byte value is
byte-reversed separately (i.e. not as a 16-byte unit). lfiwax/stfiwx
load or store the lower 4 bytes of a floating-point register from/to
memory; lfiwax sets the upper 4 bytes of the FP register to the sign
extension of the value loaded.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/align.c')
-rw-r--r-- | arch/powerpc/kernel/align.c | 57 |
1 files changed, 49 insertions, 8 deletions
diff --git a/arch/powerpc/kernel/align.c b/arch/powerpc/kernel/align.c index 5c9ff7f5c44e..4c47f9cc0d9a 100644 --- a/arch/powerpc/kernel/align.c +++ b/arch/powerpc/kernel/align.c @@ -38,7 +38,7 @@ struct aligninfo { /* Bits in the flags field */ #define LD 0 /* load */ #define ST 1 /* store */ -#define SE 2 /* sign-extend value */ +#define SE 2 /* sign-extend value, or FP ld/st as word */ #define F 4 /* to/from fp regs */ #define U 8 /* update index register */ #define M 0x10 /* multiple load/store */ @@ -87,9 +87,9 @@ static struct aligninfo aligninfo[128] = { { 8, LD+F+U }, /* 00 1 1001: lfdu */ { 4, ST+F+S+U }, /* 00 1 1010: stfsu */ { 8, ST+F+U }, /* 00 1 1011: stfdu */ - INVALID, /* 00 1 1100 */ + { 16, LD+F }, /* 00 1 1100: lfdp */ INVALID, /* 00 1 1101 */ - INVALID, /* 00 1 1110 */ + { 16, ST+F }, /* 00 1 1110: stfdp */ INVALID, /* 00 1 1111 */ { 8, LD }, /* 01 0 0000: ldx */ INVALID, /* 01 0 0001 */ @@ -167,10 +167,10 @@ static struct aligninfo aligninfo[128] = { { 8, LD+F }, /* 11 0 1001: lfdx */ { 4, ST+F+S }, /* 11 0 1010: stfsx */ { 8, ST+F }, /* 11 0 1011: stfdx */ - INVALID, /* 11 0 1100 */ - { 8, LD+M }, /* 11 0 1101: lmd */ - INVALID, /* 11 0 1110 */ - { 8, ST+M }, /* 11 0 1111: stmd */ + { 16, LD+F }, /* 11 0 1100: lfdpx */ + { 4, LD+F+SE }, /* 11 0 1101: lfiwax */ + { 16, ST+F }, /* 11 0 1110: stfdpx */ + { 4, ST+F }, /* 11 0 1111: stfiwx */ { 4, LD+U }, /* 11 1 0000: lwzux */ INVALID, /* 11 1 0001 */ { 4, ST+U }, /* 11 1 0010: stwux */ @@ -356,6 +356,42 @@ static int emulate_multiple(struct pt_regs *regs, unsigned char __user *addr, return 1; } +/* + * Emulate floating-point pair loads and stores. + * Only POWER6 has these instructions, and it does true little-endian, + * so we don't need the address swizzling. + */ +static int emulate_fp_pair(struct pt_regs *regs, unsigned char __user *addr, + unsigned int reg, unsigned int flags) +{ + char *ptr = (char *) ¤t->thread.fpr[reg]; + int i, ret; + + if (!(flags & F)) + return 0; + if (reg & 1) + return 0; /* invalid form: FRS/FRT must be even */ + if (!(flags & SW)) { + /* not byte-swapped - easy */ + if (!(flags & ST)) + ret = __copy_from_user(ptr, addr, 16); + else + ret = __copy_to_user(addr, ptr, 16); + } else { + /* each FPR value is byte-swapped separately */ + ret = 0; + for (i = 0; i < 16; ++i) { + if (!(flags & ST)) + ret |= __get_user(ptr[i^7], addr + i); + else + ret |= __put_user(ptr[i^7], addr + i); + } + } + if (ret) + return -EFAULT; + return 1; /* exception handled and fixed up */ +} + /* * Called on alignment exception. Attempts to fixup @@ -471,6 +507,10 @@ int fix_alignment(struct pt_regs *regs) flush_fp_to_thread(current); } + /* Special case for 16-byte FP loads and stores */ + if (nb == 16) + return emulate_fp_pair(regs, addr, reg, flags); + /* If we are loading, get the data from user space, else * get it from register values */ @@ -531,7 +571,8 @@ int fix_alignment(struct pt_regs *regs) * or floating point single precision conversion */ switch (flags & ~(U|SW)) { - case LD+SE: /* sign extend */ + case LD+SE: /* sign extending integer loads */ + case LD+F+SE: /* sign extend for lfiwax */ if ( nb == 2 ) data.ll = data.x16.low16; else /* nb must be 4 */ |