diff mbox series

powerpc/32: Fix FPR index validation and fpscr access

Message ID 20220610101851.246538-1-ariel.miculas@gmail.com (mailing list archive)
State Superseded
Headers show
Series powerpc/32: Fix FPR index validation and fpscr access | expand

Commit Message

Ariel Miculas June 10, 2022, 10:18 a.m. UTC 
From: Ariel Miculas <ariel.miculas@belden.com>

On PPC32, there are two indexes used for each FPR.

The last two indexes into the imaginary address space "USER area" are
used to access fpscr instead of the FPR registers. Fix the validation
condition so that the access of the FPR array doesn't overflow into
fpscr.  Also split the access of fpscr into high part and low part.

Signed-off-by: Ariel Miculas <ariel.miculas@belden.com>
---
 arch/powerpc/kernel/ptrace/ptrace-fpu.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/ptrace/ptrace-fpu.c b/arch/powerpc/kernel/ptrace/ptrace-fpu.c
index 09c49632bfe5..eabc05b439f1 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-fpu.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-fpu.c
@@ -17,14 +17,18 @@  int ptrace_get_fpr(struct task_struct *child, int index, unsigned long *data)
 
 #ifdef CONFIG_PPC_FPU_REGS
 	flush_fp_to_thread(child);
-	if (fpidx < (PT_FPSCR - PT_FPR0)) {
-		if (IS_ENABLED(CONFIG_PPC32))
+	if (IS_ENABLED(CONFIG_PPC32)) {
+		if ((fpidx >> 1) < (PT_FPSCR - PT_FPR0) >> 1)
 			// On 32-bit the index we are passed refers to 32-bit words
 			*data = ((u32 *)child->thread.fp_state.fpr)[fpidx];
 		else
+			*data = ((u32 *)&child->thread.fp_state.fpscr)[fpidx & 1];
+	} else {
+		if (fpidx < (PT_FPSCR - PT_FPR0))
 			memcpy(data, &child->thread.TS_FPR(fpidx), sizeof(long));
-	} else
-		*data = child->thread.fp_state.fpscr;
+		else
+			*data = child->thread.fp_state.fpscr;
+	}
 #else
 	*data = 0;
 #endif
@@ -43,14 +47,18 @@  int ptrace_put_fpr(struct task_struct *child, int index, unsigned long data)
 
 #ifdef CONFIG_PPC_FPU_REGS
 	flush_fp_to_thread(child);
-	if (fpidx < (PT_FPSCR - PT_FPR0)) {
-		if (IS_ENABLED(CONFIG_PPC32))
+	if (IS_ENABLED(CONFIG_PPC32)) {
+		if ((fpidx >> 1) < (PT_FPSCR - PT_FPR0) >> 1)
 			// On 32-bit the index we are passed refers to 32-bit words
 			((u32 *)child->thread.fp_state.fpr)[fpidx] = data;
 		else
+			((u32 *)&child->thread.fp_state.fpscr)[fpidx & 1] = data;
+	} else {
+		if (fpidx < (PT_FPSCR - PT_FPR0))
 			memcpy(&child->thread.TS_FPR(fpidx), &data, sizeof(long));
-	} else
-		child->thread.fp_state.fpscr = data;
+		else
+			child->thread.fp_state.fpscr = data;
+	}
 #endif
 
 	return 0;