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powerpc/code-patching: Inline is_offset_in_{cond}_branch_range()

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Test in is_offset_in_branch_range() and is_offset_in_cond_branch_range()
are simple tests that are worth inlining.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a05be0ccb7373e6a9789a1988fcd0c810f5f9269.1652074503.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2022-05-09 07:36:01 +02:00 committed by Michael Ellerman
parent ae3a2a2188
commit 1acbf27e8a
2 changed files with 27 additions and 29 deletions
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29
arch/powerpc/include/asm/code-patching.h
View file

@ -24,8 +24,33 @@
DECLARE_STATIC_KEY_FALSE(init_mem_is_free);
bool is_offset_in_branch_range(long offset);
bool is_offset_in_cond_branch_range(long offset);
/*
* Powerpc branch instruction is :
*
* 0 6 30 31
* +---------+----------------+---+---+
* | opcode | LI |AA |LK |
* +---------+----------------+---+---+
* Where AA = 0 and LK = 0
*
* LI is a signed 24 bits integer. The real branch offset is computed
* by: imm32 = SignExtend(LI:'0b00', 32);
*
* So the maximum forward branch should be:
* (0x007fffff << 2) = 0x01fffffc = 0x1fffffc
* The maximum backward branch should be:
* (0xff800000 << 2) = 0xfe000000 = -0x2000000
*/
static inline bool is_offset_in_branch_range(long offset)
{
return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));
}
static inline bool is_offset_in_cond_branch_range(long offset)
{
return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);
}
int create_branch(ppc_inst_t *instr, const u32 *addr,
unsigned long target, int flags);
int create_cond_branch(ppc_inst_t *instr, const u32 *addr,

27
arch/powerpc/lib/code-patching.c
View file

@ -214,33 +214,6 @@ int patch_branch(u32 *addr, unsigned long target, int flags)
return patch_instruction(addr, instr);
}
bool is_offset_in_branch_range(long offset)
{
/*
* Powerpc branch instruction is :
*
* 0 6 30 31
* +---------+----------------+---+---+
* | opcode | LI |AA |LK |
* +---------+----------------+---+---+
* Where AA = 0 and LK = 0
*
* LI is a signed 24 bits integer. The real branch offset is computed
* by: imm32 = SignExtend(LI:'0b00', 32);
*
* So the maximum forward branch should be:
* (0x007fffff << 2) = 0x01fffffc = 0x1fffffc
* The maximum backward branch should be:
* (0xff800000 << 2) = 0xfe000000 = -0x2000000
*/
return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));
}
bool is_offset_in_cond_branch_range(long offset)
{
return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);
}
/*
* Helper to check if a given instruction is a conditional branch
* Derived from the conditional checks in analyse_instr()