From: Michael Ellerman <mpe@ellerman.id.au>
To: <linuxppc-dev@lists.ozlabs.org>
Cc: erhard_f@mailbox.org, wangkefeng.wang@huawei.com, npiggin@gmail.com
Subject: [PATCH 3/6] powerpc/85xx: Fix virt_to_phys() off-by-one in smp_85xx_start_cpu()
Date: Thu, 7 Apr 2022 00:57:59 +1000 [thread overview]
Message-ID: <20220406145802.538416-3-mpe@ellerman.id.au> (raw)
In-Reply-To: <20220406145802.538416-1-mpe@ellerman.id.au>
In smp_85xx_start_cpu() we are passed an address but we're unsure if
it's a real or virtual address, so there's a check to determine that.
The check has an off-by-one in that it tests if the address is greater
than high_memory, but high_memory is the first address of high memory,
so the check should be greater-or-equal.
It seems this has never been a problem in practice, but it also triggers
the DEBUG_VIRTUAL checks in __pa() which we would like to avoid. We can
fix both issues by converting high_memory - 1 to a physical address and
testing against that.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/platforms/85xx/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index a1c6a7827c8f..9c43cf32f4c9 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -208,7 +208,7 @@ static int smp_85xx_start_cpu(int cpu)
* The bootpage and highmem can be accessed via ioremap(), but
* we need to directly access the spinloop if its in lowmem.
*/
- ioremappable = *cpu_rel_addr > virt_to_phys(high_memory);
+ ioremappable = *cpu_rel_addr > virt_to_phys(high_memory - 1);
/* Map the spin table */
if (ioremappable)
--
2.34.1
next prev parent reply other threads:[~2022-04-06 14:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-06 14:57 [PATCH 1/6] powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit Michael Ellerman
2022-04-06 14:57 ` [PATCH 2/6] Revert "powerpc: Set max_mapnr correctly" Michael Ellerman
2022-04-06 14:57 ` Michael Ellerman [this message]
2022-05-15 10:21 ` [PATCH 3/6] powerpc/85xx: Fix virt_to_phys() off-by-one in smp_85xx_start_cpu() Michael Ellerman
2022-04-06 14:58 ` [PATCH 4/6] powerpc/vas: Fix __pa() handling in init_winctx_regs() Michael Ellerman
2022-04-06 14:58 ` [PATCH 5/6] powerpc/64: Only WARN if __pa()/__va() called with bad addresses Michael Ellerman
2022-04-06 15:18 ` Christophe Leroy
2022-04-08 4:01 ` Michael Ellerman
2022-04-06 14:58 ` [RFC PATCH 6/6] powerpc/mm: Add virt_addr_valid() checks Michael Ellerman
2022-04-10 12:27 ` [PATCH 1/6] powerpc: Fix virt_addr_valid() for 64-bit Book3E & 32-bit Michael Ellerman
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