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ARM: 8431/1: fix alignement of __bug_table section entries

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On old ARM chips, unaligned accesses to memory are not trapped and
fixed.  On module load, symbols are relocated, and the relocation of
__bug_table symbols is done on a u32 basis. Yet the section is not
aligned to a multiple of 4 address, but to a multiple of 2.

This triggers an Oops on pxa architecture, where address 0xbf0021ea
is the first relocation in the __bug_table section :
  apply_relocate(): pxa3xx_nand: section 13 reloc 0 sym ''
  Unable to handle kernel paging request at virtual address bf0021ea
  pgd = e1cd0000
  [bf0021ea] *pgd=c1cce851, *pte=c1cde04f, *ppte=c1cde01f
  Internal error: Oops: 23 [#1] ARM
  Modules linked in:
  CPU: 0 PID: 606 Comm: insmod Not tainted 4.2.0-rc8-next-20150828-cm-x300+ #887
  Hardware name: CM-X300 module
  task: e1c68700 ti: e1c3e000 task.ti: e1c3e000
  PC is at apply_relocate+0x2f4/0x3d4
  LR is at 0xbf0021ea
  pc : [<c000e7c8>]    lr : [<bf0021ea>]    psr: 80000013
  sp : e1c3fe30  ip : 60000013  fp : e49e8c60
  r10: e49e8fa8  r9 : 00000000  r8 : e49e7c58
  r7 : e49e8c38  r6 : e49e8a58  r5 : e49e8920  r4 : e49e8918
  r3 : bf0021ea  r2 : bf007034  r1 : 00000000  r0 : bf000000
  Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
  Control: 0000397f  Table: c1cd0018  DAC: 00000051
  Process insmod (pid: 606, stack limit = 0xe1c3e198)
  [<c000e7c8>] (apply_relocate) from [<c005ce5c>] (load_module+0x1248/0x1f5c)
  [<c005ce5c>] (load_module) from [<c005dc54>] (SyS_init_module+0xe4/0x170)
  [<c005dc54>] (SyS_init_module) from [<c000a420>] (ret_fast_syscall+0x0/0x38)

Fix this by ensuring entries in __bug_table are all aligned to at least
of multiple of 4. This transforms a module section  __bug_table as :
-   [12] __bug_table       PROGBITS        00000000 002232 000018 00   A  0   0  1
+   [12] __bug_table       PROGBITS        00000000 002232 000018 00   A  0   0  4

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Robert Jarzmik 2015-09-11 17:12:27 +01:00 committed by Russell King
parent a077224fd3
commit a4a5a7379e
1 changed files with 1 additions and 0 deletions
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1
arch/arm/include/asm/bug.h
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@ -40,6 +40,7 @@ do { \
"2:\t.asciz " #__file "\n" \
".popsection\n" \
".pushsection __bug_table,\"a\"\n" \
".align 2\n" \
"3:\t.word 1b, 2b\n" \
"\t.hword " #__line ", 0\n" \
".popsection"); \