From 4890ae46911c99d61fb622605c2d81bf8c86b209 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Tue, 18 Oct 2016 13:46:27 +0100 Subject: [PATCH] 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 Acked-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/kernel/probes/simulate-insn.c | 16 +++++++--------- 1 file 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 #include #include #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 -- 2.45.2