powerpc/ptrace: split out ADV_DEBUG_REGS related functions.

Move ADV_DEBUG_REGS functions out of ptrace.c, into
ptrace-adv.c and ptrace-noadv.c
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: Squash in fixup patch from Christophe]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e2bd7d275bd5933d848aad4fee3ca652a14d039b.1582848567.git.christophe.leroy@c-s.fr

arch/powerpc/kernel/ptrace/Makefile

@@ -14,3 +14,7 @@ endif
 obj-$(CONFIG_ALTIVEC)		+= ptrace-altivec.o
 obj-$(CONFIG_SPE)		+= ptrace-spe.o
 obj-$(CONFIG_PPC_TRANSACTIONAL_MEM)	+= ptrace-tm.o
+obj-$(CONFIG_PPC_ADV_DEBUG_REGS)	+= ptrace-adv.o
+ifneq ($(CONFIG_PPC_ADV_DEBUG_REGS),y)
+obj-y				+= ptrace-noadv.o
+endif

arch/powerpc/kernel/ptrace/ptrace-decl.h

@@ -174,3 +174,8 @@ int tm_cgpr32_set(struct task_struct *target, const struct user_regset *regset,
 /* ptrace-view */
 
 extern const struct user_regset_view user_ppc_native_view;
+
+/* ptrace-(no)adv */
+int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data);
+long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_info);
+long ppc_del_hwdebug(struct task_struct *child, long data);

arch/powerpc/kernel/ptrace/ptrace-noadv.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/regset.h>
+#include <linux/hw_breakpoint.h>
+
+#include <asm/debug.h>
+
+#include "ptrace-decl.h"
+
+void user_enable_single_step(struct task_struct *task)
+{
+	struct pt_regs *regs = task->thread.regs;
+
+	if (regs != NULL) {
+		regs->msr &= ~MSR_BE;
+		regs->msr |= MSR_SE;
+	}
+	set_tsk_thread_flag(task, TIF_SINGLESTEP);
+}
+
+void user_enable_block_step(struct task_struct *task)
+{
+	struct pt_regs *regs = task->thread.regs;
+
+	if (regs != NULL) {
+		regs->msr &= ~MSR_SE;
+		regs->msr |= MSR_BE;
+	}
+	set_tsk_thread_flag(task, TIF_SINGLESTEP);
+}
+
+void user_disable_single_step(struct task_struct *task)
+{
+	struct pt_regs *regs = task->thread.regs;
+
+	if (regs != NULL)
+		regs->msr &= ~(MSR_SE | MSR_BE);
+
+	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+}
+
+int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data)
+{
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	int ret;
+	struct thread_struct *thread = &task->thread;
+	struct perf_event *bp;
+	struct perf_event_attr attr;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+	bool set_bp = true;
+	struct arch_hw_breakpoint hw_brk;
+
+	/* For ppc64 we support one DABR and no IABR's at the moment (ppc64).
+	 *  For embedded processors we support one DAC and no IAC's at the
+	 *  moment.
+	 */
+	if (addr > 0)
+		return -EINVAL;
+
+	/* The bottom 3 bits in dabr are flags */
+	if ((data & ~0x7UL) >= TASK_SIZE)
+		return -EIO;
+
+	/* For processors using DABR (i.e. 970), the bottom 3 bits are flags.
+	 *  It was assumed, on previous implementations, that 3 bits were
+	 *  passed together with the data address, fitting the design of the
+	 *  DABR register, as follows:
+	 *
+	 *  bit 0: Read flag
+	 *  bit 1: Write flag
+	 *  bit 2: Breakpoint translation
+	 *
+	 *  Thus, we use them here as so.
+	 */
+
+	/* Ensure breakpoint translation bit is set */
+	if (data && !(data & HW_BRK_TYPE_TRANSLATE))
+		return -EIO;
+	hw_brk.address = data & (~HW_BRK_TYPE_DABR);
+	hw_brk.type = (data & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
+	hw_brk.len = DABR_MAX_LEN;
+	hw_brk.hw_len = DABR_MAX_LEN;
+	set_bp = (data) && (hw_brk.type & HW_BRK_TYPE_RDWR);
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	bp = thread->ptrace_bps[0];
+	if (!set_bp) {
+		if (bp) {
+			unregister_hw_breakpoint(bp);
+			thread->ptrace_bps[0] = NULL;
+		}
+		return 0;
+	}
+	if (bp) {
+		attr = bp->attr;
+		attr.bp_addr = hw_brk.address;
+		attr.bp_len = DABR_MAX_LEN;
+		arch_bp_generic_fields(hw_brk.type, &attr.bp_type);
+
+		/* Enable breakpoint */
+		attr.disabled = false;
+
+		ret =  modify_user_hw_breakpoint(bp, &attr);
+		if (ret)
+			return ret;
+
+		thread->ptrace_bps[0] = bp;
+		thread->hw_brk = hw_brk;
+		return 0;
+	}
+
+	/* Create a new breakpoint request if one doesn't exist already */
+	hw_breakpoint_init(&attr);
+	attr.bp_addr = hw_brk.address;
+	attr.bp_len = DABR_MAX_LEN;
+	arch_bp_generic_fields(hw_brk.type,
+			       &attr.bp_type);
+
+	thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr,
+					       ptrace_triggered, NULL, task);
+	if (IS_ERR(bp)) {
+		thread->ptrace_bps[0] = NULL;
+		return PTR_ERR(bp);
+	}
+
+#else /* !CONFIG_HAVE_HW_BREAKPOINT */
+	if (set_bp && (!ppc_breakpoint_available()))
+		return -ENODEV;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+	task->thread.hw_brk = hw_brk;
+	return 0;
+}
+
+long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_info)
+{
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	int len = 0;
+	struct thread_struct *thread = &child->thread;
+	struct perf_event *bp;
+	struct perf_event_attr attr;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+	struct arch_hw_breakpoint brk;
+
+	if (bp_info->version != 1)
+		return -ENOTSUPP;
+	/*
+	 * We only support one data breakpoint
+	 */
+	if ((bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_RW) == 0 ||
+	    (bp_info->trigger_type & ~PPC_BREAKPOINT_TRIGGER_RW) != 0 ||
+	    bp_info->condition_mode != PPC_BREAKPOINT_CONDITION_NONE)
+		return -EINVAL;
+
+	if ((unsigned long)bp_info->addr >= TASK_SIZE)
+		return -EIO;
+
+	brk.address = bp_info->addr & ~HW_BREAKPOINT_ALIGN;
+	brk.type = HW_BRK_TYPE_TRANSLATE;
+	brk.len = DABR_MAX_LEN;
+	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_READ)
+		brk.type |= HW_BRK_TYPE_READ;
+	if (bp_info->trigger_type & PPC_BREAKPOINT_TRIGGER_WRITE)
+		brk.type |= HW_BRK_TYPE_WRITE;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE)
+		len = bp_info->addr2 - bp_info->addr;
+	else if (bp_info->addr_mode == PPC_BREAKPOINT_MODE_EXACT)
+		len = 1;
+	else
+		return -EINVAL;
+	bp = thread->ptrace_bps[0];
+	if (bp)
+		return -ENOSPC;
+
+	/* Create a new breakpoint request if one doesn't exist already */
+	hw_breakpoint_init(&attr);
+	attr.bp_addr = (unsigned long)bp_info->addr;
+	attr.bp_len = len;
+	arch_bp_generic_fields(brk.type, &attr.bp_type);
+
+	bp = register_user_hw_breakpoint(&attr, ptrace_triggered, NULL, child);
+	thread->ptrace_bps[0] = bp;
+	if (IS_ERR(bp)) {
+		thread->ptrace_bps[0] = NULL;
+		return PTR_ERR(bp);
+	}
+
+	return 1;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
+	if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)
+		return -EINVAL;
+
+	if (child->thread.hw_brk.address)
+		return -ENOSPC;
+
+	if (!ppc_breakpoint_available())
+		return -ENODEV;
+
+	child->thread.hw_brk = brk;
+
+	return 1;
+}
+
+long ppc_del_hwdebug(struct task_struct *child, long data)
+{
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	int ret = 0;
+	struct thread_struct *thread = &child->thread;
+	struct perf_event *bp;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+	if (data != 1)
+		return -EINVAL;
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	bp = thread->ptrace_bps[0];
+	if (bp) {
+		unregister_hw_breakpoint(bp);
+		thread->ptrace_bps[0] = NULL;
+	} else {
+		ret = -ENOENT;
+	}
+	return ret;
+#else /* CONFIG_HAVE_HW_BREAKPOINT */
+	if (child->thread.hw_brk.address == 0)
+		return -ENOENT;
+
+	child->thread.hw_brk.address = 0;
+	child->thread.hw_brk.type = 0;
+#endif /* CONFIG_HAVE_HW_BREAKPOINT */
+
+	return 0;
+}