path: root/arch/powerpc/kernel/signal_32.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Signal handling for 32bit PPC and 32bit tasks on 64bit PPC
 *
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 * Copyright (C) 2001 IBM
 * Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
 *
 *  Derived from "arch/i386/kernel/signal.c"
 *    Copyright (C) 1991, 1992 Linus Torvalds
 *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/elf.h>
#include <linux/ptrace.h>
#include <linux/pagemap.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
#ifdef CONFIG_PPC64
#include <linux/compat.h>
#else
#include <linux/wait.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#endif

#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/syscalls.h>
#include <asm/sigcontext.h>
#include <asm/vdso.h>
#include <asm/switch_to.h>
#include <asm/tm.h>
#include <asm/asm-prototypes.h>
#ifdef CONFIG_PPC64
#include "ppc32.h"
#include <asm/unistd.h>
#else
#include <asm/ucontext.h>
#include <asm/pgtable.h>
#endif

#include "signal.h"


#ifdef CONFIG_PPC64
#define old_sigaction	old_sigaction32
#define sigcontext	sigcontext32
#define mcontext	mcontext32
#define ucontext	ucontext32

#define __save_altstack __compat_save_altstack

/*
 * Userspace code may pass a ucontext which doesn't include VSX added
 * at the end.  We need to check for this case.
 */
#define UCONTEXTSIZEWITHOUTVSX \
		(sizeof(struct ucontext) - sizeof(elf_vsrreghalf_t32))

/*
 * Returning 0 means we return to userspace via
 * ret_from_except and thus restore all user
 * registers from *regs.  This is what we need
 * to do when a signal has been delivered.
 */

#define GP_REGS_SIZE	min(sizeof(elf_gregset_t32), sizeof(struct pt_regs32))
#undef __SIGNAL_FRAMESIZE
#define __SIGNAL_FRAMESIZE	__SIGNAL_FRAMESIZE32
#undef ELF_NVRREG
#define ELF_NVRREG	ELF_NVRREG32

/*
 * Functions for flipping sigsets (thanks to brain dead generic
 * implementation that makes things simple for little endian only)
 */
static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
{
	return put_compat_sigset(uset, set, sizeof(*uset));
}

static inline int get_sigset_t(sigset_t *set,
			       const compat_sigset_t __user *uset)
{
	return get_compat_sigset(set, uset);
}

#define to_user_ptr(p)		ptr_to_compat(p)
#define from_user_ptr(p)	compat_ptr(p)

static inline int save_general_regs(struct pt_regs *regs,
		struct mcontext __user *frame)
{
	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
	int i;
	/* Force usr to alway see softe as 1 (interrupts enabled) */
	elf_greg_t64 softe = 0x1;

	WARN_ON(!FULL_REGS(regs));

	for (i = 0; i <= PT_RESULT; i ++) {
		if (i == 14 && !FULL_REGS(regs))
			i = 32;
		if ( i == PT_SOFTE) {
			if(__put_user((unsigned int)softe, &frame->mc_gregs[i]))
				return -EFAULT;
			else
				continue;
		}
		if (__put_user((unsigned int)gregs[i], &frame->mc_gregs[i]))
			return -EFAULT;
	}
	return 0;
}

static inline int restore_general_regs(struct pt_regs *regs,
		struct mcontext __user *sr)
{
	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;
	int i;

	for (i = 0; i <= PT_RESULT; i++) {
		if ((i == PT_MSR) || (i == PT_SOFTE))
			continue;
		if (__get_user(gregs[i], &sr->mc_gregs[i]))
			return -EFAULT;
	}
	return 0;
}

#else /* CONFIG_PPC64 */

#define GP_REGS_SIZE	min(sizeof(elf_gregset_t), sizeof(struct pt_regs))

static inline int put_sigset_t(sigset_t __user *uset, sigset_t *set)
{
	return copy_to_user(uset, set, sizeof(*uset));
}

static inline int get_sigset_t(sigset_t *set, const sigset_t __user *uset)
{
	return copy_from_user(set, uset, sizeof(*uset));
}

#define to_user_ptr(p)		((unsigned long)(p))
#define from_user_ptr(p)	((void __user *)(p))

static inline int save_general_regs(struct pt_regs *regs,
		struct mcontext __user *frame)
{
	WARN_ON(!FULL_REGS(regs));
	return __copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE);
}

static inline int restore_general_regs(struct pt_regs *regs,
		struct mcontext __user *sr)
{
	/* copy up to but not including MSR */
	if (__copy_from_user(regs, &sr->mc_gregs,
				PT_MSR * sizeof(elf_greg_t)))
		return -EFAULT;
	/* copy from orig_r3 (the word after the MSR) up to the end */
	if (__copy_from_user(&regs->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3],
				GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t)))
		return -EFAULT;
	return 0;
}
#endif

/*
 * When we have signals to deliver, we set up on the
 * user stack, going down from the original stack pointer:
 *	an ABI gap of 56 words
 *	an mcontext struct
 *	a sigcontext struct
 *	a gap of __SIGNAL_FRAMESIZE bytes
 *
 * Each of these things must be a multiple of 16 bytes in size. The following
 * structure represent all of this except the __SIGNAL_FRAMESIZE gap
 *
 */
struct sigframe {
	struct sigcontext sctx;		/* the sigcontext */
	struct mcontext	mctx;		/* all the register values */
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	struct sigcontext sctx_transact;
	struct mcontext	mctx_transact;
#endif
	/*
	 * Programs using the rs6000/xcoff abi can save up to 19 gp
	 * regs and 18 fp regs below sp before decrementing it.
	 */
	int			abigap[56];
};

/* We use the mc_pad field for the signal return trampoline. */
#define tramp	mc_pad

/*
 *  When we have rt signals to deliver, we set up on the
 *  user stack, going down from the original stack pointer:
 *	one rt_sigframe struct (siginfo + ucontext + ABI gap)
 *	a gap of __SIGNAL_FRAMESIZE+16 bytes
 *  (the +16 is to get the siginfo and ucontext in the same
 *  positions as in older kernels).
 *
 *  Each of these things must be a multiple of 16 bytes in size.
 *
 */
struct rt_sigframe {
#ifdef CONFIG_PPC64
	compat_siginfo_t info;
#else
	struct siginfo info;
#endif
	struct ucontext	uc;
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	struct ucontext	uc_transact;
#endif
	/*
	 * Programs using the rs6000/xcoff abi can save up to 19 gp
	 * regs and 18 fp regs below sp before decrementing it.
	 */
	int			abigap[56];
};

#ifdef CONFIG_VSX
unsigned long copy_fpr_to_user(void __user *to,
			       struct task_struct *task)
{
	u64 buf[ELF_NFPREG];
	int i;

	/* save FPR copy to local buffer then write to the thread_struct */
	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
		buf[i] = task->thread.TS_FPR(i);
	buf[i] = task->thread.fp_state.fpscr;
	return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
}

unsigned long copy_fpr_from_user(struct task_struct *task,
				 void __user *from)
{
	u64 buf[ELF_NFPREG];
	int i;

	if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
		return 1;
	for (i = 0; i < (ELF_NFPREG - 1) ; i++)
		task->thread.TS_FPR(i) = buf[i];
	task->thread.fp_state.fpscr = buf[i];

	return 0;
}

unsigned long copy_vsx_to_user(void __user *to,
			       struct task_struct *task)
{
	u64 buf[ELF_NVSRHALFREG];
	int i;

	/* save FPR copy to local buffer then write to the thread_struct */
	for (i = 0; i < ELF_NVSRHALFREG; i++)
		buf[i] = task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
	return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
}

unsigned long copy_vsx_from_user(struct task_struct *task,
				 void __user *from)
{
	u64 buf[ELF_NVSRHALFREG];
	int i;

	if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
		return 1;
	for (i = 0; i < ELF_NVSRHALFREG ; i++)
		task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
	return 0;
}

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
unsigned long copy_ckfpr_to_user(void __user *to,
				  struct task_