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Differential D41583

nehemiah RNG: Switch to using FPU_KERN_NOCTX
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Authored by jhb on Aug 24 2023, 4:23 PM.
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markj
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rG90ac116d5e46: nehemiah RNG: Switch to using FPU_KERN_NOCTX
rG7aec088cbce8: nehemiah RNG: Switch to using FPU_KERN_NOCTX

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rG FreeBSD src repository
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Buildable 53276
Build 50167: arc lint + arc unit

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sys/
dev/
random/
24 lines

Diff 126477

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sys/dev/random/nehemiah.c

Show All 37 Lines
#include <machine/segments.h> #include <machine/segments.h>
#include <machine/pcb.h> #include <machine/pcb.h>
#include <machine/md_var.h> #include <machine/md_var.h>
#include <machine/specialreg.h> #include <machine/specialreg.h>
#include <dev/random/randomdev.h> #include <dev/random/randomdev.h>
static void random_nehemiah_init(void);
static void random_nehemiah_deinit(void);
static u_int random_nehemiah_read(void *, u_int); static u_int random_nehemiah_read(void *, u_int);
static struct random_source random_nehemiah = { static struct random_source random_nehemiah = {
.rs_ident = "VIA Nehemiah Padlock RNG", .rs_ident = "VIA Nehemiah Padlock RNG",
.rs_source = RANDOM_PURE_NEHEMIAH, .rs_source = RANDOM_PURE_NEHEMIAH,
.rs_read = random_nehemiah_read .rs_read = random_nehemiah_read
}; };
static struct fpu_kern_ctx *fpu_ctx_save;
/* This H/W source never stores more than 8 bytes in one go */ /* This H/W source never stores more than 8 bytes in one go */
/* ARGSUSED */ /* ARGSUSED */
static __inline size_t static __inline size_t
VIA_RNG_store(void *buf) VIA_RNG_store(void *buf)
{ {
uint32_t retval = 0; uint32_t retval = 0;
uint32_t rate = 0; uint32_t rate = 0;
__asm __volatile( __asm __volatile(
"movl $0,%%edx\n\t" "movl $0,%%edx\n\t"
".byte 0x0f, 0xa7, 0xc0" ".byte 0x0f, 0xa7, 0xc0"
: "=a" (retval), "+d" (rate), "+D" (buf) : "=a" (retval), "+d" (rate), "+D" (buf)
: :
: "memory" : "memory"
); );
if (rate == 0) if (rate == 0)
return (retval&0x1f); return (retval&0x1f);
return (0); return (0);
} }
static void
random_nehemiah_init(void)
{
fpu_ctx_save = fpu_kern_alloc_ctx(FPU_KERN_NORMAL);
}
static void
random_nehemiah_deinit(void)
{
fpu_kern_free_ctx(fpu_ctx_save);
}
/* It is specifically allowed that buf is a multiple of sizeof(long) */ /* It is specifically allowed that buf is a multiple of sizeof(long) */
static u_int static u_int
random_nehemiah_read(void *buf, u_int c) random_nehemiah_read(void *buf, u_int c)
{ {
uint8_t *b; uint8_t *b;
size_t count, ret; size_t count, ret;
uint64_t tmp; uint64_t tmp;
fpu_kern_enter(curthread, fpu_ctx_save, FPU_KERN_NORMAL); fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX);
b = buf; b = buf;
for (count = c; count > 0; count -= ret) { for (count = c; count > 0; count -= ret) {
ret = MIN(VIA_RNG_store(&tmp), count); ret = MIN(VIA_RNG_store(&tmp), count);
memcpy(b, &tmp, ret); memcpy(b, &tmp, ret);
b += ret; b += ret;
} }
fpu_kern_leave(curthread, fpu_ctx_save); fpu_kern_leave(curthread, NULL);
return (c); return (c);
} }
static int static int
nehemiah_modevent(module_t mod, int type, void *unused) nehemiah_modevent(module_t mod, int type, void *unused)
{ {
int error = 0; int error = 0;
switch (type) { switch (type) {
case MOD_LOAD: case MOD_LOAD:
if (via_feature_rng & VIA_HAS_RNG) { if (via_feature_rng & VIA_HAS_RNG) {
random_source_register(&random_nehemiah); random_source_register(&random_nehemiah);
printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident); printf("random: fast provider: \"%s\"\n", random_nehemiah.rs_ident);
random_nehemiah_init();
} }
break; break;
case MOD_UNLOAD: case MOD_UNLOAD:
if (via_feature_rng & VIA_HAS_RNG) { if (via_feature_rng & VIA_HAS_RNG) {
random_nehemiah_deinit();
random_source_deregister(&random_nehemiah); random_source_deregister(&random_nehemiah);
} }
break; break;
case MOD_SHUTDOWN: case MOD_SHUTDOWN:
break; break;
default: default:
Show All 17 Lines