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-rw-r--r--arch/powerpc/kernel/hw_breakpoint_constraints.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/hw_breakpoint_constraints.c b/arch/powerpc/kernel/hw_breakpoint_constraints.c
new file mode 100644
index 000000000..9e51801c4
--- /dev/null
+++ b/arch/powerpc/kernel/hw_breakpoint_constraints.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/sched.h>
+#include <asm/hw_breakpoint.h>
+#include <asm/sstep.h>
+#include <asm/cache.h>
+
+static bool dar_in_user_range(unsigned long dar, struct arch_hw_breakpoint *info)
+{
+ return ((info->address <= dar) && (dar - info->address < info->len));
+}
+
+static bool ea_user_range_overlaps(unsigned long ea, int size,
+ struct arch_hw_breakpoint *info)
+{
+ return ((ea < info->address + info->len) &&
+ (ea + size > info->address));
+}
+
+static bool dar_in_hw_range(unsigned long dar, struct arch_hw_breakpoint *info)
+{
+ unsigned long hw_start_addr, hw_end_addr;
+
+ hw_start_addr = ALIGN_DOWN(info->address, HW_BREAKPOINT_SIZE);
+ hw_end_addr = ALIGN(info->address + info->len, HW_BREAKPOINT_SIZE);
+
+ return ((hw_start_addr <= dar) && (hw_end_addr > dar));
+}
+
+static bool ea_hw_range_overlaps(unsigned long ea, int size,
+ struct arch_hw_breakpoint *info)
+{
+ unsigned long hw_start_addr, hw_end_addr;
+ unsigned long align_size = HW_BREAKPOINT_SIZE;
+
+ /*
+ * On p10 predecessors, quadword is handle differently then
+ * other instructions.
+ */
+ if (!cpu_has_feature(CPU_FTR_ARCH_31) && size == 16)
+ align_size = HW_BREAKPOINT_SIZE_QUADWORD;
+
+ hw_start_addr = ALIGN_DOWN(info->address, align_size);
+ hw_end_addr = ALIGN(info->address + info->len, align_size);
+
+ return ((ea < hw_end_addr) && (ea + size > hw_start_addr));
+}
+
+/*
+ * If hw has multiple DAWR registers, we also need to check all
+ * dawrx constraint bits to confirm this is _really_ a valid event.
+ * If type is UNKNOWN, but privilege level matches, consider it as
+ * a positive match.
+ */
+static bool check_dawrx_constraints(struct pt_regs *regs, int type,
+ struct arch_hw_breakpoint *info)
+{
+ if (OP_IS_LOAD(type) && !(info->type & HW_BRK_TYPE_READ))
+ return false;
+
+ /*
+ * The Cache Management instructions other than dcbz never
+ * cause a match. i.e. if type is CACHEOP, the instruction
+ * is dcbz, and dcbz is treated as Store.
+ */
+ if ((OP_IS_STORE(type) || type == CACHEOP) && !(info->type & HW_BRK_TYPE_WRITE))
+ return false;
+
+ if (is_kernel_addr(regs->nip) && !(info->type & HW_BRK_TYPE_KERNEL))
+ return false;
+
+ if (user_mode(regs) && !(info->type & HW_BRK_TYPE_USER))
+ return false;
+
+ return true;
+}
+
+/*
+ * Return true if the event is valid wrt dawr configuration,
+ * including extraneous exception. Otherwise return false.
+ */
+bool wp_check_constraints(struct pt_regs *regs, ppc_inst_t instr,
+ unsigned long ea, int type, int size,
+ struct arch_hw_breakpoint *info)
+{
+ bool in_user_range = dar_in_user_range(regs->dar, info);
+ bool dawrx_constraints;
+
+ /*
+ * 8xx supports only one breakpoint and thus we can
+ * unconditionally return true.
+ */
+ if (IS_ENABLED(CONFIG_PPC_8xx)) {
+ if (!in_user_range)
+ info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+ return true;
+ }
+
+ if (unlikely(ppc_inst_equal(instr, ppc_inst(0)))) {
+ if (cpu_has_feature(CPU_FTR_ARCH_31) &&
+ !dar_in_hw_range(regs->dar, info))
+ return false;
+
+ return true;
+ }
+
+ dawrx_constraints = check_dawrx_constraints(regs, type, info);
+
+ if (type == UNKNOWN) {
+ if (cpu_has_feature(CPU_FTR_ARCH_31) &&
+ !dar_in_hw_range(regs->dar, info))
+ return false;
+
+ return dawrx_constraints;
+ }
+
+ if (ea_user_range_overlaps(ea, size, info))
+ return dawrx_constraints;
+
+ if (ea_hw_range_overlaps(ea, size, info)) {
+ if (dawrx_constraints) {
+ info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
+ return true;
+ }
+ }
+ return false;
+}
+
+void wp_get_instr_detail(struct pt_regs *regs, ppc_inst_t *instr,
+ int *type, int *size, unsigned long *ea)
+{
+ struct instruction_op op;
+ int err;
+
+ pagefault_disable();
+ err = __get_user_instr(*instr, (void __user *)regs->nip);
+ pagefault_enable();
+
+ if (err)
+ return;
+
+ analyse_instr(&op, regs, *instr);
+ *type = GETTYPE(op.type);
+ *ea = op.ea;
+
+ if (!(regs->msr & MSR_64BIT))
+ *ea &= 0xffffffffUL;
+
+
+ *size = GETSIZE(op.type);
+ if (*type == CACHEOP) {
+ *size = l1_dcache_bytes();
+ *ea &= ~(*size - 1);
+ } else if (*type == LOAD_VMX || *type == STORE_VMX) {
+ *ea &= ~(*size - 1);
+ }
+}