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arch: arm: cortex_m: Update APIs to save and restore FPU context #93057

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arch: arm: cortex_m: Update APIs to save and restore FPU context #93057

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4a47084
Added missing #includes for used types
msmttchr Jul 12, 2025
a1ea5dd
Introduced an API to support scenarios where FPU sharing across threads
msmttchr Jul 12, 2025
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18 changes: 16 additions & 2 deletions arch/arm/core/cortex_m/fpu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@

void z_arm_save_fp_context(struct fpu_ctx_full *buffer)
{
#if defined(CONFIG_FPU_SHARING)
#if defined(CONFIG_FPU)
__ASSERT_NO_MSG(buffer != NULL);

uint32_t CONTROL = __get_CONTROL();
Expand Down Expand Up @@ -44,7 +44,7 @@ void z_arm_save_fp_context(struct fpu_ctx_full *buffer)

void z_arm_restore_fp_context(const struct fpu_ctx_full *buffer)
{
#if defined(CONFIG_FPU_SHARING)
#if defined(CONFIG_FPU)
if (buffer->ctx_saved) {
/* Set FPCA first so it is set even if an interrupt happens
* during restoration.
Expand All @@ -61,3 +61,17 @@ void z_arm_restore_fp_context(const struct fpu_ctx_full *buffer)
}
#endif
}

void z_arm_save_shared_fp_context(struct fpu_ctx_full *buffer)
{
#if defined(CONFIG_FPU_SHARING)
z_arm_save_fp_context(buffer);
#endif
}

void z_arm_restore_shared_fp_context(struct fpu_ctx_full *buffer)
{
#if defined(CONFIG_FPU_SHARING)
z_arm_restore_fp_context(buffer);
#endif
}
5 changes: 5 additions & 0 deletions include/zephyr/arch/arm/cortex_m/fpu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,9 @@
#ifndef ZEPHYR_INCLUDE_ARCH_ARM_CORTEX_M_FPU_H_
#define ZEPHYR_INCLUDE_ARCH_ARM_CORTEX_M_FPU_H_

#include <stdint.h>
#include <stdbool.h>

struct fpu_ctx_full {
uint32_t caller_saved[16];
uint32_t callee_saved[16];
Expand All @@ -16,5 +19,7 @@ struct fpu_ctx_full {

void z_arm_save_fp_context(struct fpu_ctx_full *buffer);
void z_arm_restore_fp_context(const struct fpu_ctx_full *buffer);
void z_arm_save_shared_fp_context(struct fpu_ctx_full *buffer)
void z_arm_restore_shared_fp_context(const struct fpu_ctx_full *buffer);

#endif /* ZEPHYR_INCLUDE_ARCH_ARM_CORTEX_M_FPU_H_ */
4 changes: 2 additions & 2 deletions modules/trusted-firmware-m/interface/interface.c
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Original file line number Diff line number Diff line change
Expand Up @@ -55,11 +55,11 @@ int32_t tfm_ns_interface_dispatch(veneer_fn fn,

struct fpu_ctx_full context_buffer;

z_arm_save_fp_context(&context_buffer);
z_arm_save_shared_fp_context(&context_buffer);

result = fn(arg0, arg1, arg2, arg3);

z_arm_restore_fp_context(&context_buffer);
z_arm_restore_shared_fp_context(&context_buffer);

if (!isr_mode) {
#if !defined(CONFIG_ARM_NONSECURE_PREEMPTIBLE_SECURE_CALLS)
Expand Down
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