Commit 8f6cc75a authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: move norestart trap flag to bit 0 



Compact the trap flags down to use the low 4 bits of regs.trap.

A few 64e interrupt trap numbers set bit 4. Although they tended to be
trivial so it wasn't a real problem[1], it is not the right thing to do,
and confusing.

[*] E.g., 0x310 hypercall goes to unknown_exception, which prints
    regs->trap directly so 0x310 will appear fine, and only the syscall
    interrupt will test norestart, so it won't be confused by 0x310.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-12-npiggin@gmail.com
parent 8dc7f022

arch/powerpc/include/asm/ptrace.h

+11 −6
Original line number Diff line number Diff line
@@ -185,20 +185,25 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) 
#define current_pt_regs() \

	((struct pt_regs *)((unsigned long)task_stack_page(current) + THREAD_SIZE) - 1)



/*

 * The 4 low bits (0xf) are available as flags to overload the trap word,

 * because interrupt vectors have minimum alignment of 0x10. TRAP_FLAGS_MASK

 * must cover the bits used as flags, including bit 0 which is used as the

 * "norestart" bit.

 */

#ifdef __powerpc64__

#define TRAP_FLAGS_MASK		0x10

#define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)

#define TRAP_FLAGS_MASK		0x1

#else

/*

 * On 4xx we use bit 1 in the trap word to indicate whether the exception

 * is a critical exception (1 means it is).

 */

#define TRAP_FLAGS_MASK		0x1E

#define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)

#define TRAP_FLAGS_MASK		0xf

#define IS_CRITICAL_EXC(regs)	(((regs)->trap & 2) != 0)

#define IS_MCHECK_EXC(regs)	(((regs)->trap & 4) != 0)

#define IS_DEBUG_EXC(regs)	(((regs)->trap & 8) != 0)

#endif /* __powerpc64__ */

#define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)



static __always_inline void set_trap(struct pt_regs *regs, unsigned long val)

{
@@ -222,12 +227,12 @@ static inline bool trap_is_syscall(struct pt_regs *regs) 


static inline bool trap_norestart(struct pt_regs *regs)

{

	return regs->trap & 0x10;

	return regs->trap & 0x1;

}



static __always_inline void set_trap_norestart(struct pt_regs *regs)

{

	regs->trap |= 0x10;

	regs->trap |= 0x1;

}



#define arch_has_single_step()	(1)