adafruit-mirror/zephyr
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 9

riscv: pmp: abstract the MPRV catchall entry and its QEMU workaround

Browse source 
This will be needed at more than one location.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2024-07-08 16:34:00 -04:00 committed by Anas Nashif
parent 6138a11acc
commit 0207c7ff73
1 changed files with 29 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

47
arch/riscv/core/pmp.c
View file

@ -204,6 +204,34 @@ static bool set_pmp_entry(unsigned int *index_p, uint8_t perm,
return ok;
}
static inline bool set_pmp_mprv_catchall(unsigned int *index_p,
unsigned long *pmp_addr, unsigned long *pmp_cfg,
unsigned int index_limit)
{
/*
* We'll be using MPRV. Make a fallback entry with everything
* accessible as if no PMP entries were matched which is otherwise
* the default behavior for m-mode without MPRV.
*/
bool ok = set_pmp_entry(index_p, PMP_R | PMP_W | PMP_X,
0, 0, pmp_addr, pmp_cfg, index_limit);
#ifdef CONFIG_QEMU_TARGET
if (ok) {
/*
* Workaround: The above produced 0x1fffffff which is correct.
* But there is a QEMU bug that prevents it from interpreting
* this value correctly. Hardcode the special case used by
* QEMU to bypass this bug for now. The QEMU fix is here:
* https://lists.gnu.org/archive/html/qemu-devel/2022-04/msg00961.html
*/
pmp_addr[*index_p - 1] = -1L;
}
#endif
return ok;
}
/**
* @brief Write a range of PMP entries to corresponding PMP registers
*
@ -429,24 +457,7 @@ void z_riscv_pmp_stackguard_prepare(struct k_thread *thread)
set_pmp_entry(&index, PMP_NONE,
stack_bottom, Z_RISCV_STACK_GUARD_SIZE,
PMP_M_MODE(thread));
/*
* We'll be using MPRV. Make a fallback entry with everything
* accessible as if no PMP entries were matched which is otherwise
* the default behavior for m-mode without MPRV.
*/
set_pmp_entry(&index, PMP_R | PMP_W | PMP_X,
0, 0, PMP_M_MODE(thread));
#ifdef CONFIG_QEMU_TARGET
/*
* Workaround: The above produced 0x1fffffff which is correct.
* But there is a QEMU bug that prevents it from interpreting this
* value correctly. Hardcode the special case used by QEMU to
* bypass this bug for now. The QEMU fix is here:
* https://lists.gnu.org/archive/html/qemu-devel/2022-04/msg00961.html
*/
thread->arch.m_mode_pmpaddr_regs[index-1] = -1L;
#endif
set_pmp_mprv_catchall(&index, PMP_M_MODE(thread));
/* remember how many entries we use */
thread->arch.m_mode_pmp_end_index = index;