From 912000e73ee8fcb97831b123c9c3a7274b71cab7 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 4 Jun 2007 15:15:46 +1000 Subject: [PATCH] [POWERPC] Allow ptrace write to pt_regs trap and orig_r3 This patch allows a ptracer to write to the "trap" and "orig_r3" words of the pt_regs. This, along with a subsequent patch to the signal restart code, should enable gdb to properly handle syscall restarting after executing a separate function (at least when there's no restart block). This patch also removes ptrace32.c code toying directly with the registers and makes it use the ptrace_get/put_reg() accessors for everything so that the logic for checking what is permitted is in only one place. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/ptrace.c | 9 ++++++--- arch/powerpc/kernel/ptrace32.c | 27 ++++++++++++++------------- 2 files changed, 20 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index c9c330d35c..dd4837c4a6 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -75,10 +75,15 @@ int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data) if (task->thread.regs == NULL) return -EIO; - if (regno <= PT_MAX_PUT_REG) { + if (regno <= PT_MAX_PUT_REG || regno == PT_TRAP) { if (regno == PT_MSR) data = (data & MSR_DEBUGCHANGE) | (task->thread.regs->msr & ~MSR_DEBUGCHANGE); + /* We prevent mucking around with the reserved area of trap + * which are used internally by the kernel + */ + if (regno == PT_TRAP) + data &= 0xfff0; ((unsigned long *)task->thread.regs)[regno] = data; return 0; } @@ -409,8 +414,6 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) break; CHECK_FULL_REGS(child->thread.regs); - if (index == PT_ORIG_R3) - break; if (index < PT_FPR0) { ret = ptrace_put_reg(child, index, data); } else { diff --git a/arch/powerpc/kernel/ptrace32.c b/arch/powerpc/kernel/ptrace32.c index 4511b42299..aae6a988e1 100644 --- a/arch/powerpc/kernel/ptrace32.c +++ b/arch/powerpc/kernel/ptrace32.c @@ -206,7 +206,9 @@ long compat_sys_ptrace(int request, int pid, unsigned long addr, else part = 0; /* want the 1st half of the register (left-most). */ - /* Validate the input - check to see if address is on the wrong boundary or beyond the end of the user area */ + /* Validate the input - check to see if address is on the wrong boundary + * or beyond the end of the user area + */ if ((addr & 3) || numReg > PT_FPSCR) break; @@ -270,8 +272,6 @@ long compat_sys_ptrace(int request, int pid, unsigned long addr, if ((addr & 3) || (index > PT_FPSCR32)) break; - if (index == PT_ORIG_R3) - break; if (index < PT_FPR0) { ret = ptrace_put_reg(child, index, data); } else { @@ -302,24 +302,25 @@ long compat_sys_ptrace(int request, int pid, unsigned long addr, /* Determine which register the user wants */ index = (u64)addr >> 2; numReg = index / 2; + /* * Validate the input - check to see if address is on the * wrong boundary or beyond the end of the user area */ if ((addr & 3) || (numReg > PT_FPSCR)) break; - /* Insure it is a register we let them change */ - if ((numReg == PT_ORIG_R3) - || ((numReg > PT_CCR) && (numReg < PT_FPR0))) - break; - if (numReg >= PT_FPR0) { + if (numReg < PT_FPR0) { + unsigned long freg = ptrace_get_reg(child, numReg); + if (index % 2) + freg = (freg & ~0xfffffffful) | (data & 0xfffffffful); + else + freg = (freg & 0xfffffffful) | (data << 32); + ret = ptrace_put_reg(child, numReg, freg); + } else { flush_fp_to_thread(child); + ((unsigned int *)child->thread.regs)[index] = data; + ret = 0; } - if (numReg == PT_MSR) - data = (data & MSR_DEBUGCHANGE) - | (child->thread.regs->msr & ~MSR_DEBUGCHANGE); - ((u32*)child->thread.regs)[index] = data; - ret = 0; break; } -- 2.39.5