leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

powerpc/64s: Fix scv implicit soft-mask table for relocated kernels

Browse Source 
The implict soft-mask table addresses get relocated if they use a
relative symbol like a label. This is right for code that runs relocated
but not for unrelocated. The scv interrupt vectors run unrelocated, so
absolute addresses are required for their soft-mask table entry.

This fixes crashing with relocated kernels, usually an asynchronous
interrupt hitting in the scv handler, then hitting the trap that checks
whether r1 is in userspace.

Fixes: 325678fd05 ("powerpc/64s: add a table of implicit soft-masked addresses")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210820103431.1701240-1-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin
2021-08-20 20:34:31 +10:00
committed by Michael Ellerman
parent 310d2e83cb
commit 787c70f2f9
1 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
arch/powerpc/kernel/exceptions-64s.S
View File

@@ -812,7 +812,6 @@ __start_interrupts:
* syscall register convention is in Documentation/powerpc/syscall64-abi.rst * syscall register convention is in Documentation/powerpc/syscall64-abi.rst
*/ */
EXC_VIRT_BEGIN(system_call_vectored, 0x3000, 0x1000) EXC_VIRT_BEGIN(system_call_vectored, 0x3000, 0x1000)
1:
/* SCV 0 */ /* SCV 0 */
mr r9,r13 mr r9,r13
GET_PACA(r13) GET_PACA(r13)
@@ -842,10 +841,12 @@ EXC_VIRT_BEGIN(system_call_vectored, 0x3000, 0x1000)
b system_call_vectored_sigill b system_call_vectored_sigill
#endif #endif
.endr .endr
2:
EXC_VIRT_END(system_call_vectored, 0x3000, 0x1000) EXC_VIRT_END(system_call_vectored, 0x3000, 0x1000)
SOFT_MASK_TABLE(1b, 2b) // Treat scv vectors as soft-masked, see comment above. // Treat scv vectors as soft-masked, see comment above.
// Use absolute values rather than labels here, so they don't get relocated,
// because this code runs unrelocated.
SOFT_MASK_TABLE(0xc000000000003000, 0xc000000000004000)
#ifdef CONFIG_RELOCATABLE #ifdef CONFIG_RELOCATABLE
TRAMP_VIRT_BEGIN(system_call_vectored_tramp) TRAMP_VIRT_BEGIN(system_call_vectored_tramp)