[PATCH v3 09/10] powerpc/fsl_booke: Update of TLBCAMs after init

From: Christophe Leroy
Date: Mon Oct 25 2021 - 17:50:03 EST


After init, set readonly memory as ROX and set readwrite
memory as RWX, if STRICT_KERNEL_RWX is enabled.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
v3: No change
v2: No change
---
arch/powerpc/mm/mmu_decl.h | 2 +-
arch/powerpc/mm/nohash/fsl_book3e.c | 32 +++++++++++++++++++++++++----
2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index e13a3c0caa02..0dd4c18f8363 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -168,7 +168,7 @@ static inline phys_addr_t v_block_mapped(unsigned long va) { return 0; }
static inline unsigned long p_block_mapped(phys_addr_t pa) { return 0; }
#endif

-#if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_PPC_8xx)
+#if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_PPC_8xx) || defined(CONFIG_PPC_FSL_BOOK3E)
void mmu_mark_initmem_nx(void);
void mmu_mark_rodata_ro(void);
#else
diff --git a/arch/powerpc/mm/nohash/fsl_book3e.c b/arch/powerpc/mm/nohash/fsl_book3e.c
index 88132cab3442..b231a54f540c 100644
--- a/arch/powerpc/mm/nohash/fsl_book3e.c
+++ b/arch/powerpc/mm/nohash/fsl_book3e.c
@@ -182,7 +182,7 @@ static unsigned long map_mem_in_cams_addr(phys_addr_t phys, unsigned long virt,
/* Calculate CAM values */
for (i = 0; boundary && i < max_cam_idx; i++) {
unsigned long cam_sz;
- pgprot_t prot = PAGE_KERNEL_X;
+ pgprot_t prot = init ? PAGE_KERNEL_X : PAGE_KERNEL_ROX;

cam_sz = calc_cam_sz(boundary, virt, phys);
if (!dryrun)
@@ -195,7 +195,7 @@ static unsigned long map_mem_in_cams_addr(phys_addr_t phys, unsigned long virt,
}
for (ram -= amount_mapped; ram && i < max_cam_idx; i++) {
unsigned long cam_sz;
- pgprot_t prot = PAGE_KERNEL_X;
+ pgprot_t prot = init ? PAGE_KERNEL_X : PAGE_KERNEL;

cam_sz = calc_cam_sz(ram, virt, phys);
if (!dryrun)
@@ -210,8 +210,13 @@ static unsigned long map_mem_in_cams_addr(phys_addr_t phys, unsigned long virt,
if (dryrun)
return amount_mapped;

- loadcam_multi(0, i, max_cam_idx);
- tlbcam_index = i;
+ if (init) {
+ loadcam_multi(0, i, max_cam_idx);
+ tlbcam_index = i;
+ } else {
+ loadcam_multi(0, i, 0);
+ WARN_ON(i > tlbcam_index);
+ }

#ifdef CONFIG_PPC64
get_paca()->tcd.esel_next = i;
@@ -280,6 +285,25 @@ void __init adjust_total_lowmem(void)
memblock_set_current_limit(memstart_addr + __max_low_memory);
}

+#ifdef CONFIG_STRICT_KERNEL_RWX
+void mmu_mark_rodata_ro(void)
+{
+ /* Everything is done in mmu_mark_initmem_nx() */
+}
+#endif
+
+void mmu_mark_initmem_nx(void)
+{
+ unsigned long remapped;
+
+ if (!strict_kernel_rwx_enabled())
+ return;
+
+ remapped = map_mem_in_cams(__max_low_memory, CONFIG_LOWMEM_CAM_NUM, false, false);
+
+ WARN_ON(__max_low_memory != remapped);
+}
+
void setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size)
{
--
2.31.1