This function measures whether the FPU/SSE state can be touched in
interrupt context. If the interrupted code is in user space or has no
valid FPU/SSE context (CR0.TS == 1), FPU/SSE state can be used in IRQ
or soft_irq context too.
This is used by AES-NI accelerated AES implementation and PCLMULQDQ
accelerated GHASH implementation.
v3:
- Renamed to irq_fpu_usable to reflect the purpose of the function.
v2:
- Renamed to irq_is_fpu_using to reflect the real situation.
Signed-off-by: Huang Ying <[email protected]>
CC: H. Peter Anvin <[email protected]>
---
arch/x86/crypto/aesni-intel_glue.c | 17 +++++------------
arch/x86/include/asm/i387.h | 8 ++++++++
2 files changed, 13 insertions(+), 12 deletions(-)
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -59,13 +59,6 @@ asmlinkage void aesni_cbc_enc(struct cry
asmlinkage void aesni_cbc_dec(struct crypto_aes_ctx *ctx, u8 *out,
const u8 *in, unsigned int len, u8 *iv);
-static inline int kernel_fpu_using(void)
-{
- if (in_interrupt() && !(read_cr0() & X86_CR0_TS))
- return 1;
- return 0;
-}
-
static inline struct crypto_aes_ctx *aes_ctx(void *raw_ctx)
{
unsigned long addr = (unsigned long)raw_ctx;
@@ -89,7 +82,7 @@ static int aes_set_key_common(struct cry
return -EINVAL;
}
- if (kernel_fpu_using())
+ if (irq_fpu_usable())
err = crypto_aes_expand_key(ctx, in_key, key_len);
else {
kernel_fpu_begin();
@@ -110,7 +103,7 @@ static void aes_encrypt(struct crypto_tf
{
struct crypto_aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(tfm));
- if (kernel_fpu_using())
+ if (irq_fpu_usable())
crypto_aes_encrypt_x86(ctx, dst, src);
else {
kernel_fpu_begin();
@@ -123,7 +116,7 @@ static void aes_decrypt(struct crypto_tf
{
struct crypto_aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(tfm));
- if (kernel_fpu_using())
+ if (irq_fpu_usable())
crypto_aes_decrypt_x86(ctx, dst, src);
else {
kernel_fpu_begin();
@@ -349,7 +342,7 @@ static int ablk_encrypt(struct ablkciphe
struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
struct async_aes_ctx *ctx = crypto_ablkcipher_ctx(tfm);
- if (kernel_fpu_using()) {
+ if (irq_fpu_usable()) {
struct ablkcipher_request *cryptd_req =
ablkcipher_request_ctx(req);
memcpy(cryptd_req, req, sizeof(*req));
@@ -370,7 +363,7 @@ static int ablk_decrypt(struct ablkciphe
struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
struct async_aes_ctx *ctx = crypto_ablkcipher_ctx(tfm);
- if (kernel_fpu_using()) {
+ if (irq_fpu_usable()) {
struct ablkcipher_request *cryptd_req =
ablkcipher_request_ctx(req);
memcpy(cryptd_req, req, sizeof(*req));
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -301,6 +301,14 @@ static inline void kernel_fpu_end(void)
preempt_enable();
}
+static inline bool irq_fpu_usable(void)
+{
+ struct pt_regs *regs;
+
+ return !in_interrupt() || !(regs = get_irq_regs()) || \
+ user_mode(regs) || (read_cr0() & X86_CR0_TS);
+}
+
/*
* Some instructions like VIA's padlock instructions generate a spurious
* DNA fault but don't modify SSE registers. And these instructions