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Commit bc826666 authored by Michael Neuling's avatar Michael Neuling Committed by Paul Mackerras
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powerpc: Fix ptrace compat wrapper for FPU register access 



The ptrace compat wrapper mishandles access to the fpu registers.  The
PTRACE_PEEKUSR and PTRACE_POKEUSR requests miscalculate the index into
the fpr array due to the broken FPINDEX macro.  The
PPC_PTRACE_PEEKUSR_3264 request needs to use the same formula that the
native ptrace interface uses when operating on the register number (as
opposed to the 4-byte offset).  The PPC_PTRACE_POKEUSR_3264 request
didn't take TS_FPRWIDTH into account.

Signed-off-by: default avatarAndreas Schwab <schwab@linux-m68k.org>
Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent c7d07fdd

arch/powerpc/kernel/ptrace32.c

+11 −4
Original line number Original line Diff line number Diff line
@@ -67,7 +67,8 @@ static long compat_ptrace_old(struct task_struct *child, long request, 
/* Macros to workout the correct index for the FPR in the thread struct */

/* Macros to workout the correct index for the FPR in the thread struct */

#define FPRNUMBER(i) (((i) - PT_FPR0) >> 1)

#define FPRNUMBER(i) (((i) - PT_FPR0) >> 1)

#define FPRHALF(i) (((i) - PT_FPR0) & 1)

#define FPRHALF(i) (((i) - PT_FPR0) & 1)

#define FPRINDEX(i) TS_FPRWIDTH * FPRNUMBER(i) + FPRHALF(i)

#define FPRINDEX(i) TS_FPRWIDTH * FPRNUMBER(i) * 2 + FPRHALF(i)

#define FPRINDEX_3264(i) (TS_FPRWIDTH * ((i) - PT_FPR0))





long compat_arch_ptrace(struct task_struct *child, compat_long_t request,

long compat_arch_ptrace(struct task_struct *child, compat_long_t request,

			compat_ulong_t caddr, compat_ulong_t cdata)

			compat_ulong_t caddr, compat_ulong_t cdata)
@@ -168,8 +169,9 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, 
		CHECK_FULL_REGS(child->thread.regs);

		CHECK_FULL_REGS(child->thread.regs);

		if (numReg >= PT_FPR0) {

		if (numReg >= PT_FPR0) {

			flush_fp_to_thread(child);

			flush_fp_to_thread(child);

			tmp = ((unsigned long int *)child->thread.fpr)

			/* get 64 bit FPR */

				[FPRINDEX(numReg)];

			tmp = ((u64 *)child->thread.fpr)

				[FPRINDEX_3264(numReg)];

		} else { /* register within PT_REGS struct */

		} else { /* register within PT_REGS struct */

			tmp = ptrace_get_reg(child, numReg);

			tmp = ptrace_get_reg(child, numReg);

		} 

		}
@@ -262,8 +264,13 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, 
				freg = (freg & 0xfffffffful) | (data << 32);

				freg = (freg & 0xfffffffful) | (data << 32);

			ret = ptrace_put_reg(child, numReg, freg);

			ret = ptrace_put_reg(child, numReg, freg);

		} else {

		} else {

			u64 *tmp;

			flush_fp_to_thread(child);

			flush_fp_to_thread(child);

			((unsigned int *)child->thread.regs)[index] = data;

			/* get 64 bit FPR ... */

			tmp = &(((u64 *)child->thread.fpr)

				[FPRINDEX_3264(numReg)]);

			/* ... write the 32 bit part we want */

			((u32 *)tmp)[index % 2] = data;

			ret = 0;

			ret = 0;

		}

		}

		break;

		break;