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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-04 12:24:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-04 12:24:05 -0700
commit6203838dec05352bc357625b1e9ba0a10d3bca35 (patch)
treefa90de52b18e4d99e2280e98ae581a457184d1d9
parentaa1be08f52585fe36ecfaf5bddfdc784eb4c94cf (diff)
parent12f363511d47f86c49b7766c349989cb33fd61a8 (diff)
Merge tag 'powerpc-5.1-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fix from Michael Ellerman: "One regression fix. Changes we merged to STRICT_KERNEL_RWX on 32-bit were causing crashes under load on some machines depending on memory layout. Thanks to Christophe Leroy" * tag 'powerpc-5.1-7' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/32s: Fix BATs setting with CONFIG_STRICT_KERNEL_RWX
-rw-r--r--arch/powerpc/mm/ppc_mmu_32.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/powerpc/mm/ppc_mmu_32.c b/arch/powerpc/mm/ppc_mmu_32.c
index f29d2f118b44..5d9c3ff728c9 100644
--- a/arch/powerpc/mm/ppc_mmu_32.c
+++ b/arch/powerpc/mm/ppc_mmu_32.c
@@ -98,10 +98,20 @@ static int find_free_bat(void)
return -1;
}
+/*
+ * This function calculates the size of the larger block usable to map the
+ * beginning of an area based on the start address and size of that area:
+ * - max block size is 8M on 601 and 256 on other 6xx.
+ * - base address must be aligned to the block size. So the maximum block size
+ * is identified by the lowest bit set to 1 in the base address (for instance
+ * if base is 0x16000000, max size is 0x02000000).
+ * - 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 max_size = (cpu_has_feature(CPU_FTR_601) ? 8 : 256) << 20;
- unsigned int base_shift = (fls(base) - 1) & 31;
+ unsigned int base_shift = (ffs(base) - 1) & 31;
unsigned int block_shift = (fls(top - base) - 1) & 31;
return min3(max_size, 1U << base_shift, 1U << block_shift);
@@ -157,7 +167,7 @@ static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long to
unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
{
- int done;
+ unsigned long done;
unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET;
if (__map_without_bats) {
@@ -169,10 +179,10 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
return __mmu_mapin_ram(base, top);
done = __mmu_mapin_ram(base, border);
- if (done != border - base)
+ if (done != border)
return done;
- return done + __mmu_mapin_ram(border, top);
+ return __mmu_mapin_ram(border, top);
}
void mmu_mark_initmem_nx(void)