When errors occur in the computation of the linear address, -1L is returned. Rather than having a separate return path for errors, the variable used to return the computed linear address can be initialized with the error value. Hence, only one return path is needed. This makes the function easier to read.
While here, ensure that the error value is -1L, a 64-bit value, rather than -1, a 32-bit value. Cc: Borislav Petkov <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Adam Buchbinder <[email protected]> Cc: Colin Ian King <[email protected]> Cc: Lorenzo Stoakes <[email protected]> Cc: Qiaowei Ren <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Nathan Howard <[email protected]> Cc: Adan Hawthorn <[email protected]> Cc: Joe Perches <[email protected]> Cc: Ravi V. Shankar <[email protected]> Cc: [email protected] Suggested-by: Borislav Petkov <[email protected]> Signed-off-by: Ricardo Neri <[email protected]> --- arch/x86/mm/mpx.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index 9ceaa95..f4c48a0 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -138,7 +138,7 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs, */ static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs) { - unsigned long addr, base, indx; + unsigned long addr = -1L, base, indx; int addr_offset, base_offset, indx_offset; insn_byte_t sib; @@ -149,17 +149,17 @@ static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs) if (X86_MODRM_MOD(insn->modrm.value) == 3) { addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM); if (addr_offset < 0) - goto out_err; + goto out; addr = regs_get_register(regs, addr_offset); } else { if (insn->sib.nbytes) { base_offset = get_reg_offset(insn, regs, REG_TYPE_BASE); if (base_offset < 0) - goto out_err; + goto out; indx_offset = get_reg_offset(insn, regs, REG_TYPE_INDEX); if (indx_offset < 0) - goto out_err; + goto out; base = regs_get_register(regs, base_offset); indx = regs_get_register(regs, indx_offset); @@ -167,14 +167,13 @@ static void __user *mpx_get_addr_ref(struct insn *insn, struct pt_regs *regs) } else { addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM); if (addr_offset < 0) - goto out_err; + goto out; addr = regs_get_register(regs, addr_offset); } addr += insn->displacement.value; } +out: return (void __user *)addr; -out_err: - return (void __user *)-1; } static int mpx_insn_decode(struct insn *insn, -- 2.7.4
