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stm32h7: Fix Protected user SRAM placement and attributes. #19983

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Merged
xiaoxiang781216 merged 2 commits into from
Aug 28, 2026
Merged

stm32h7: Fix Protected user SRAM placement and attributes. #19983

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a186e9a
stm32h7: Use the selected SRAM end for the protected user heap.
13022591351 Aug 26, 2026
a475478
stm32h7: Keep protected user SRAM non-shareable.
13022591351 Aug 26, 2026
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10 changes: 5 additions & 5 deletions arch/arm/src/stm32h7/stm32_allocateheap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -253,15 +253,15 @@ void up_allocate_heap(void **heap_start, size_t *heap_size)
DEBUGASSERT(ubase < (uintptr_t)SRAM_END);

/* Adjust that size to account for MPU alignment requirements.
* NOTE that there is an implicit assumption that the SRAM123_END
* is aligned to the MPU requirement.
* NOTE that there is an implicit assumption that SRAM_END is aligned
* to the MPU requirement.
*/

log2 = (int)mpu_log2regionfloor(usize);
DEBUGASSERT((SRAM_END & ((1 << log2) - 1)) == 0);

usize = (1 << log2);
ubase = SRAM123_END - usize;
ubase = SRAM_END - usize;

/* Return the user-space heap settings */

Expand Down Expand Up @@ -320,8 +320,8 @@ void up_allocate_kheap(void **heap_start, size_t *heap_size)
DEBUGASSERT(ubase < (uintptr_t)SRAM_END);

/* Adjust that size to account for MPU alignment requirements.
* NOTE that there is an implicit assumption that the SRAM123_END
* is aligned to the MPU requirement.
* NOTE that there is an implicit assumption that SRAM_END is aligned
* to the MPU requirement.
*/

log2 = (int)mpu_log2regionfloor(usize);
Expand Down
24 changes: 22 additions & 2 deletions arch/arm/src/stm32h7/stm32_mpuinit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,26 @@
# endif
#endif

/****************************************************************************
* Private Functions
****************************************************************************/

#ifdef CONFIG_BUILD_PROTECTED
static void stm32_mpu_user_intsram(uintptr_t start, size_t size)
{
/* STM32H7 protected user memory can span AXI and D2 SRAM. Keep it
* Normal and non-shareable so that LDREX/STREX use the CPU-local
* exclusive monitor. Dual-core RPTUN shared memory is mapped separately
* below with shareable attributes.
*/

mpu_configure_region(start, size,
MPU_RASR_TEX_SO |
MPU_RASR_C |
MPU_RASR_AP_RWRW);
}
#endif

/****************************************************************************
* Public Functions
****************************************************************************/
Expand Down Expand Up @@ -94,7 +114,7 @@ void stm32_mpuinitialize(void)
mpu_user_flash(USERSPACE->us_textstart,
USERSPACE->us_textend - USERSPACE->us_textstart);

mpu_user_intsram(datastart, dataend - datastart);
stm32_mpu_user_intsram(datastart, dataend - datastart);
#endif

#ifdef CONFIG_RPTUN
Expand All @@ -121,7 +141,7 @@ void stm32_mpuinitialize(void)

void stm32_mpu_uheap(uintptr_t start, size_t size)
{
mpu_user_intsram(start, size);
stm32_mpu_user_intsram(start, size);
}
#endif

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