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| author | Robin Murphy <robin.murphy@arm.com> | 2016-10-18 13:46:27 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-11-07 18:15:03 +0000 |
| commit | 4890ae46911c99d61fb622605c2d81bf8c86b209 (patch) | |
| tree | 5d62056f1f1f9cea14cc0c658786917ae647e2ba /arch/arm64/kernel | |
| parent | be8f185d8af4dbd450023a42a48c6faa8cbcdfe6 (diff) | |
| download | lwn-4890ae46911c99d61fb622605c2d81bf8c86b209.tar.gz lwn-4890ae46911c99d61fb622605c2d81bf8c86b209.zip | |
arm64/kprobes: Tidy up sign-extension usage
Kprobes does not need its own homebrewed (and frankly inscrutable) sign
extension macro; just use the standard kernel functions instead. Since
the compiler actually recognises the sign-extension idiom of the latter,
we also get the small bonus of some nicer codegen, as each displacement
calculation helper then compiles to a single optimal SBFX instruction.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/probes/simulate-insn.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/arch/arm64/kernel/probes/simulate-insn.c b/arch/arm64/kernel/probes/simulate-insn.c index 8977ce9d009d..357d3efe1366 100644 --- a/arch/arm64/kernel/probes/simulate-insn.c +++ b/arch/arm64/kernel/probes/simulate-insn.c @@ -13,28 +13,26 @@ * General Public License for more details. */ +#include <linux/bitops.h> #include <linux/kernel.h> #include <linux/kprobes.h> #include "simulate-insn.h" -#define sign_extend(x, signbit) \ - ((x) | (0 - ((x) & (1 << (signbit))))) - #define bbl_displacement(insn) \ - sign_extend(((insn) & 0x3ffffff) << 2, 27) + sign_extend32(((insn) & 0x3ffffff) << 2, 27) #define bcond_displacement(insn) \ - sign_extend(((insn >> 5) & 0x7ffff) << 2, 20) + sign_extend32(((insn >> 5) & 0x7ffff) << 2, 20) #define cbz_displacement(insn) \ - sign_extend(((insn >> 5) & 0x7ffff) << 2, 20) + sign_extend32(((insn >> 5) & 0x7ffff) << 2, 20) #define tbz_displacement(insn) \ - sign_extend(((insn >> 5) & 0x3fff) << 2, 15) + sign_extend32(((insn >> 5) & 0x3fff) << 2, 15) #define ldr_displacement(insn) \ - sign_extend(((insn >> 5) & 0x7ffff) << 2, 20) + sign_extend32(((insn >> 5) & 0x7ffff) << 2, 20) static inline void set_x_reg(struct pt_regs *regs, int reg, u64 val) { @@ -106,7 +104,7 @@ simulate_adr_adrp(u32 opcode, long addr, struct pt_regs *regs) xn = opcode & 0x1f; imm = ((opcode >> 3) & 0x1ffffc) | ((opcode >> 29) & 0x3); - imm = sign_extend(imm, 20); + imm = sign_extend64(imm, 20); if (opcode & 0x80000000) val = (imm<<12) + (addr & 0xfffffffffffff000); else |