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powerpc/module32: Use symbolic instructions names. 

To increase readability/maintainability, replace hard coded
instructions values by symbolic names.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Leroy 2019-05-03 06:40:16 +00:00 committed by Michael Ellerman
parent 7f9c929a7f
commit 4eb4516ead
1 changed files with 16 additions and 8 deletions
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24
arch/powerpc/kernel/module_32.c
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@ -172,10 +172,12 @@ int module_frob_arch_sections(Elf32_Ehdr *hdr,
static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
{
if (entry->jump[0] == 0x3d800000 + ((val + 0x8000) >> 16)
&& entry->jump[1] == 0x398c0000 + (val & 0xffff))
return 1;
return 0;
if (entry->jump[0] != (PPC_INST_ADDIS | __PPC_RT(R12) | PPC_HA(val)))
return 0;
if (entry->jump[1] != (PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12) |
PPC_LO(val)))
return 0;
return 1;
}
/* Set up a trampoline in the PLT to bounce us to the distant function */
@ -200,10 +202,16 @@ static uint32_t do_plt_call(void *location,
entry++;
}
entry->jump[0] = 0x3d800000+((val+0x8000)>>16); /* lis r12,sym@ha */
entry->jump[1] = 0x398c0000 + (val&0xffff); /* addi r12,r12,sym@l*/
entry->jump[2] = 0x7d8903a6; /* mtctr r12 */
entry->jump[3] = 0x4e800420; /* bctr */
/*
* lis r12, sym@ha
* addi r12, r12, sym@l
* mtctr r12
* bctr
*/
entry->jump[0] = PPC_INST_ADDIS | __PPC_RT(R12) | PPC_HA(val);
entry->jump[1] = PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12) | PPC_LO(val);
entry->jump[2] = PPC_INST_MTCTR | __PPC_RS(R12);
entry->jump[3] = PPC_INST_BCTR;
pr_debug("Initialized plt for 0x%x at %p\n", val, entry);
return (uint32_t)entry;