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Message-ID: <91962818085df4f909b0d48925b6dce7c30b6467.1638779871.git.christophe.leroy@csgroup.eu>
Date: Mon, 6 Dec 2021 08:38:16 +0000
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
CC: Christophe Leroy <christophe.leroy@...roup.eu>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
Maxime Bizon <mbizon@...ebox.fr>,
"stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: [PATCH] powerpc/32s: Fix BATs allocation for KASAN
It has been reported some configuration where the kernel doesn't
boot with KASAN enabled.
This is due to wrong BAT allocation for the KASAN area:
---[ Data Block Address Translation ]---
0: 0xc0000000-0xcfffffff 0x00000000 256M Kernel rw m
1: 0xd0000000-0xdfffffff 0x10000000 256M Kernel rw m
2: 0xe0000000-0xefffffff 0x20000000 256M Kernel rw m
3: 0xf8000000-0xf9ffffff 0x2a000000 32M Kernel rw m
4: 0xfa000000-0xfdffffff 0x2c000000 64M Kernel rw m
A BAT must have both virtual and physical addresses alignment matching
the size of the BAT. This is not the case for BAT 4 above.
Fix kasan_init_region() by using block_size() function that is in
book3s32/mmu.c. To be able to reuse it here, make it non static and
change its name to bat_block_size() in order to avoid name conflict
with block_size() defined in <linux/blkdev.h>
Also reuse find_free_bat() to avoid an error message from setbat()
when no BAT is available.
With this change we get correct alignment for BATs:
---[ Data Block Address Translation ]---
0: 0xc0000000-0xcfffffff 0x00000000 256M Kernel rw
1: 0xd0000000-0xdfffffff 0x10000000 256M Kernel rw
2: 0xe0000000-0xefffffff 0x20000000 256M Kernel rw
3: 0xf8000000-0xfbffffff 0x2c000000 64M Kernel rw
4: 0xfc000000-0xfdffffff 0x2a000000 32M Kernel rw
Reported-by: Maxime Bizon <mbizon@...ebox.fr>
Fixes: 7974c4732642 ("powerpc/32s: Implement dedicated kasan_init_region()")
Cc: stable@...r.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/include/asm/book3s/32/mmu-hash.h | 2 +
arch/powerpc/mm/book3s32/mmu.c | 10 ++---
arch/powerpc/mm/kasan/book3s_32.c | 43 ++++++++++---------
3 files changed, 29 insertions(+), 26 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
index f5be185cbdf8..5b45c648a8d9 100644
--- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
@@ -143,6 +143,8 @@ static __always_inline void update_user_segments(u32 val)
update_user_segment(15, val);
}
+int find_free_bat(void);
+unsigned int bat_block_size(unsigned long base, unsigned long top);
#endif /* !__ASSEMBLY__ */
/* We happily ignore the smaller BATs on 601, we don't actually use
diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index cb48e4a5106d..9e7714a861bf 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -76,7 +76,7 @@ unsigned long p_block_mapped(phys_addr_t pa)
return 0;
}
-static int find_free_bat(void)
+int find_free_bat(void)
{
int b;
int n = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4;
@@ -100,7 +100,7 @@ static int find_free_bat(void)
* - block size has to be a power of two. This is calculated by finding the
* highest bit set to 1.
*/
-static unsigned int block_size(unsigned long base, unsigned long top)
+unsigned int bat_block_size(unsigned long base, unsigned long top)
{
unsigned int max_size = SZ_256M;
unsigned int base_shift = (ffs(base) - 1) & 31;
@@ -145,7 +145,7 @@ static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long to
int idx;
while ((idx = find_free_bat()) != -1 && base != top) {
- unsigned int size = block_size(base, top);
+ unsigned int size = bat_block_size(base, top);
if (size < 128 << 10)
break;
@@ -204,12 +204,12 @@ void mmu_mark_initmem_nx(void)
unsigned long size;
for (i = 0; i < nb - 1 && base < top && top - base > (128 << 10);) {
- size = block_size(base, top);
+ size = bat_block_size(base, top);
setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT);
base += size;
}
if (base < top) {
- size = block_size(base, top);
+ size = bat_block_size(base, top);
size = max(size, 128UL << 10);
if ((top - base) > size) {
size <<= 1;
diff --git a/arch/powerpc/mm/kasan/book3s_32.c b/arch/powerpc/mm/kasan/book3s_32.c
index 202bd260a009..c2ff93c63dfa 100644
--- a/arch/powerpc/mm/kasan/book3s_32.c
+++ b/arch/powerpc/mm/kasan/book3s_32.c
@@ -11,32 +11,33 @@ int __init kasan_init_region(void *start, size_t size)
unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);
unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);
unsigned long k_cur = k_start;
- int k_size = k_end - k_start;
- int k_size_base = 1 << (ffs(k_size) - 1);
int ret;
void *block;
- block = memblock_alloc(k_size, k_size_base);
-
- if (block && k_size_base >= SZ_128K && k_start == ALIGN(k_start, k_size_base)) {
- int k_size_more = 1 << (ffs(k_size - k_size_base) - 1);
-
- setbat(-1, k_start, __pa(block), k_size_base, PAGE_KERNEL);
- if (k_size_more >= SZ_128K)
- setbat(-1, k_start + k_size_base, __pa(block) + k_size_base,
- k_size_more, PAGE_KERNEL);
- if (v_block_mapped(k_start))
- k_cur = k_start + k_size_base;
- if (v_block_mapped(k_start + k_size_base))
- k_cur = k_start + k_size_base + k_size_more;
-
- update_bats();
+ while (k_cur < k_end) {
+ unsigned int k_size = bat_block_size(k_cur, k_end);
+ phys_addr_t phys;
+ int idx = find_free_bat();
+
+ if (idx == -1)
+ break;
+ if (k_size < SZ_128K)
+ break;
+ phys = memblock_phys_alloc(k_size, k_size);
+ if (!phys)
+ break;
+
+ setbat(idx, k_cur, phys, k_size, PAGE_KERNEL);
+ k_cur += k_size;
}
+ if (k_cur != k_start)
+ update_bats();
- if (!block)
- block = memblock_alloc(k_size, PAGE_SIZE);
- if (!block)
- return -ENOMEM;
+ if (k_cur < k_end) {
+ block = memblock_alloc(k_end - k_cur, PAGE_SIZE);
+ if (!block)
+ return -ENOMEM;
+ }
ret = kasan_init_shadow_page_tables(k_start, k_end);
if (ret)
--
2.33.1
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