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Merge pull request #8669 from douzzer/20250414-can_save_vector_registers_x86-recursive

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20250414-can_save_vector_registers_x86-recursive
This commit is contained in:
JacobBarthelmeh
2025-04-14 15:03:33 -06:00
committed by GitHub
parent bbe956cc0c ecf9982a0f
commit 43e68add96
2 changed files with 26 additions and 1 deletions
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1
.wolfssl_known_macro_extras
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@ -492,6 +492,7 @@ TCP_NODELAY
TFM_ALREADY_SET TFM_ALREADY_SET
TFM_SMALL_MONT_SET TFM_SMALL_MONT_SET
THREADED_SNIFFTEST THREADED_SNIFFTEST
TIF_NEED_FPU_LOAD
TIME_T_NOT_LONG TIME_T_NOT_LONG
TI_DUMMY_BUILD TI_DUMMY_BUILD
TLS13_RSA_PSS_SIGN_CB_NO_PREHASH TLS13_RSA_PSS_SIGN_CB_NO_PREHASH

26
linuxkm/x86_vector_register_glue.c
View File

@ -400,12 +400,34 @@ static inline void wc_linuxkm_fpu_state_release(
WARN_UNUSED_RESULT int can_save_vector_registers_x86(void) WARN_UNUSED_RESULT int can_save_vector_registers_x86(void)
{ {
/* First, check if we're already saved, per wc_linuxkm_fpu_states.
*
* On kernel >= 6.15, irq_fpu_usable() dumps a backtrace to the kernel log
* if called while already saved, so it's crucial to preempt that call by
* checking wc_linuxkm_fpu_states.
*/
struct wc_thread_fpu_count_ent *pstate = wc_linuxkm_fpu_state_assoc(0);
if ((pstate != NULL) && (pstate->fpu_state != 0U)) {
if (unlikely((pstate->fpu_state & WC_FPU_COUNT_MASK)
== WC_FPU_COUNT_MASK))
{
/* would overflow */
return 0;
} else {
return 1;
}
}
if (irq_fpu_usable()) if (irq_fpu_usable())
return 1; return 1;
else if (in_nmi() || (hardirq_count() > 0) || (softirq_count() > 0)) else if (in_nmi() || (hardirq_count() > 0) || (softirq_count() > 0))
return 0; return 0;
#ifdef TIF_NEED_FPU_LOAD
else if (test_thread_flag(TIF_NEED_FPU_LOAD)) else if (test_thread_flag(TIF_NEED_FPU_LOAD))
return 1; return 1;
#endif
return 0; return 0;
} }
@ -441,7 +463,7 @@ WARN_UNUSED_RESULT int save_vector_registers_x86(void)
} }
if (irq_fpu_usable() if (irq_fpu_usable()
#if (LINUX_VERSION_CODE < KERNEL_VERSION(5, 17, 0)) #if (LINUX_VERSION_CODE < KERNEL_VERSION(5, 17, 0)) && defined(TIF_NEED_FPU_LOAD)
/* work around a kernel bug -- see linux commit 59f5ede3bc0f0. /* work around a kernel bug -- see linux commit 59f5ede3bc0f0.
* what we really want here is this_cpu_read(in_kernel_fpu), but * what we really want here is this_cpu_read(in_kernel_fpu), but
* in_kernel_fpu is an unexported static array. * in_kernel_fpu is an unexported static array.
@ -489,6 +511,7 @@ WARN_UNUSED_RESULT int save_vector_registers_x86(void)
wc_linuxkm_fpu_state_release(pstate); wc_linuxkm_fpu_state_release(pstate);
#endif #endif
return BAD_STATE_E; return BAD_STATE_E;
#ifdef TIF_NEED_FPU_LOAD
} else if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { } else if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
static int warned_fpu_forbidden = 0; static int warned_fpu_forbidden = 0;
if (! warned_fpu_forbidden) if (! warned_fpu_forbidden)
@ -498,6 +521,7 @@ WARN_UNUSED_RESULT int save_vector_registers_x86(void)
wc_linuxkm_fpu_state_release(pstate); wc_linuxkm_fpu_state_release(pstate);
#endif #endif
return BAD_STATE_E; return BAD_STATE_E;
#endif
} else { } else {
/* assume already safely in_kernel_fpu from caller, but recursively /* assume already safely in_kernel_fpu from caller, but recursively
* preempt_disable() to be extra-safe. * preempt_disable() to be extra-safe.