diff options
Diffstat (limited to 'arch/powerpc/kernel/hw_breakpoint_constraints.c')
| -rw-r--r-- | arch/powerpc/kernel/hw_breakpoint_constraints.c | 158 |
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); + } +} |