diff options
Diffstat (limited to 'target-arm/kvm64.c')
| -rw-r--r-- | target-arm/kvm64.c | 361 |
1 files changed, 359 insertions, 2 deletions
diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c index 5f96cde603..771ecdbafe 100644 --- a/target-arm/kvm64.c +++ b/target-arm/kvm64.c @@ -2,6 +2,7 @@ * ARM implementation of KVM hooks, 64 bit specific code * * Copyright Mian-M. Hamayun 2013, Virtual Open Systems + * Copyright Alex Bennée 2014, Linaro * * This work is licensed under the terms of the GNU GPL, version 2 or later. * See the COPYING file in the top-level directory. @@ -12,13 +13,17 @@ #include <sys/types.h> #include <sys/ioctl.h> #include <sys/mman.h> +#include <sys/ptrace.h> +#include <linux/elf.h> #include <linux/kvm.h> #include "config-host.h" #include "qemu-common.h" #include "qemu/timer.h" #include "qemu/error-report.h" +#include "qemu/host-utils.h" +#include "exec/gdbstub.h" #include "sysemu/sysemu.h" #include "sysemu/kvm.h" #include "kvm_arm.h" @@ -28,20 +33,358 @@ static bool have_guest_debug; +/* + * Although the ARM implementation of hardware assisted debugging + * allows for different breakpoints per-core, the current GDB + * interface treats them as a global pool of registers (which seems to + * be the case for x86, ppc and s390). As a result we store one copy + * of registers which is used for all active cores. + * + * Write access is serialised by virtue of the GDB protocol which + * updates things. Read access (i.e. when the values are copied to the + * vCPU) is also gated by GDB's run control. + * + * This is not unreasonable as most of the time debugging kernels you + * never know which core will eventually execute your function. + */ + +typedef struct { + uint64_t bcr; + uint64_t bvr; +} HWBreakpoint; + +/* The watchpoint registers can cover more area than the requested + * watchpoint so we need to store the additional information + * somewhere. We also need to supply a CPUWatchpoint to the GDB stub + * when the watchpoint is hit. + */ +typedef struct { + uint64_t wcr; + uint64_t wvr; + CPUWatchpoint details; +} HWWatchpoint; + +/* Maximum and current break/watch point counts */ +int max_hw_bps, max_hw_wps; +GArray *hw_breakpoints, *hw_watchpoints; + +#define cur_hw_wps (hw_watchpoints->len) +#define cur_hw_bps (hw_breakpoints->len) +#define get_hw_bp(i) (&g_array_index(hw_breakpoints, HWBreakpoint, i)) +#define get_hw_wp(i) (&g_array_index(hw_watchpoints, HWWatchpoint, i)) + /** - * kvm_arm_init_debug() + * kvm_arm_init_debug() - check for guest debug capabilities * @cs: CPUState * - * Check for guest debug capabilities. + * kvm_check_extension returns the number of debug registers we have + * or 0 if we have none. * */ static void kvm_arm_init_debug(CPUState *cs) { have_guest_debug = kvm_check_extension(cs->kvm_state, KVM_CAP_SET_GUEST_DEBUG); + + max_hw_wps = kvm_check_extension(cs->kvm_state, KVM_CAP_GUEST_DEBUG_HW_WPS); + hw_watchpoints = g_array_sized_new(true, true, + sizeof(HWWatchpoint), max_hw_wps); + + max_hw_bps = kvm_check_extension(cs->kvm_state, KVM_CAP_GUEST_DEBUG_HW_BPS); + hw_breakpoints = g_array_sized_new(true, true, + sizeof(HWBreakpoint), max_hw_bps); return; } +/** + * insert_hw_breakpoint() + * @addr: address of breakpoint + * + * See ARM ARM D2.9.1 for details but here we are only going to create + * simple un-linked breakpoints (i.e. we don't chain breakpoints + * together to match address and context or vmid). The hardware is + * capable of fancier matching but that will require exposing that + * fanciness to GDB's interface + * + * D7.3.2 DBGBCR<n>_EL1, Debug Breakpoint Control Registers + * + * 31 24 23 20 19 16 15 14 13 12 9 8 5 4 3 2 1 0 + * +------+------+-------+-----+----+------+-----+------+-----+---+ + * | RES0 | BT | LBN | SSC | HMC| RES0 | BAS | RES0 | PMC | E | + * +------+------+-------+-----+----+------+-----+------+-----+---+ + * + * BT: Breakpoint type (0 = unlinked address match) + * LBN: Linked BP number (0 = unused) + * SSC/HMC/PMC: Security, Higher and Priv access control (Table D-12) + * BAS: Byte Address Select (RES1 for AArch64) + * E: Enable bit + */ +static int insert_hw_breakpoint(target_ulong addr) +{ + HWBreakpoint brk = { + .bcr = 0x1, /* BCR E=1, enable */ + .bvr = addr + }; + + if (cur_hw_bps >= max_hw_bps) { + return -ENOBUFS; + } + + brk.bcr = deposit32(brk.bcr, 1, 2, 0x3); /* PMC = 11 */ + brk.bcr = deposit32(brk.bcr, 5, 4, 0xf); /* BAS = RES1 */ + + g_array_append_val(hw_breakpoints, brk); + + return 0; +} + +/** + * delete_hw_breakpoint() + * @pc: address of breakpoint + * + * Delete a breakpoint and shuffle any above down + */ + +static int delete_hw_breakpoint(target_ulong pc) +{ + int i; + for (i = 0; i < hw_breakpoints->len; i++) { + HWBreakpoint *brk = get_hw_bp(i); + if (brk->bvr == pc) { + g_array_remove_index(hw_breakpoints, i); + return 0; + } + } + return -ENOENT; +} + +/** + * insert_hw_watchpoint() + * @addr: address of watch point + * @len: size of area + * @type: type of watch point + * + * See ARM ARM D2.10. As with the breakpoints we can do some advanced + * stuff if we want to. The watch points can be linked with the break + * points above to make them context aware. However for simplicity + * currently we only deal with simple read/write watch points. + * + * D7.3.11 DBGWCR<n>_EL1, Debug Watchpoint Control Registers + * + * 31 29 28 24 23 21 20 19 16 15 14 13 12 5 4 3 2 1 0 + * +------+-------+------+----+-----+-----+-----+-----+-----+-----+---+ + * | RES0 | MASK | RES0 | WT | LBN | SSC | HMC | BAS | LSC | PAC | E | + * +------+-------+------+----+-----+-----+-----+-----+-----+-----+---+ + * + * MASK: num bits addr mask (0=none,01/10=res,11=3 bits (8 bytes)) + * WT: 0 - unlinked, 1 - linked (not currently used) + * LBN: Linked BP number (not currently used) + * SSC/HMC/PAC: Security, Higher and Priv access control (Table D2-11) + * BAS: Byte Address Select + * LSC: Load/Store control (01: load, 10: store, 11: both) + * E: Enable + * + * The bottom 2 bits of the value register are masked. Therefore to + * break on any sizes smaller than an unaligned word you need to set + * MASK=0, BAS=bit per byte in question. For larger regions (^2) you + * need to ensure you mask the address as required and set BAS=0xff + */ + +static int insert_hw_watchpoint(target_ulong addr, + target_ulong len, int type) +{ + HWWatchpoint wp = { + .wcr = 1, /* E=1, enable */ + .wvr = addr & (~0x7ULL), + .details = { .vaddr = addr, .len = len } + }; + + if (cur_hw_wps >= max_hw_wps) { + return -ENOBUFS; + } + + /* + * HMC=0 SSC=0 PAC=3 will hit EL0 or EL1, any security state, + * valid whether EL3 is implemented or not + */ + wp.wcr = deposit32(wp.wcr, 1, 2, 3); + + switch (type) { + case GDB_WATCHPOINT_READ: + wp.wcr = deposit32(wp.wcr, 3, 2, 1); + wp.details.flags = BP_MEM_READ; + break; + case GDB_WATCHPOINT_WRITE: + wp.wcr = deposit32(wp.wcr, 3, 2, 2); + wp.details.flags = BP_MEM_WRITE; + break; + case GDB_WATCHPOINT_ACCESS: + wp.wcr = deposit32(wp.wcr, 3, 2, 3); + wp.details.flags = BP_MEM_ACCESS; + break; + default: + g_assert_not_reached(); + break; + } + if (len <= 8) { + /* we align the address and set the bits in BAS */ + int off = addr & 0x7; + int bas = (1 << len) - 1; + + wp.wcr = deposit32(wp.wcr, 5 + off, 8 - off, bas); + } else { + /* For ranges above 8 bytes we need to be a power of 2 */ + if (is_power_of_2(len)) { + int bits = ctz64(len); + + wp.wvr &= ~((1 << bits) - 1); + wp.wcr = deposit32(wp.wcr, 24, 4, bits); + wp.wcr = deposit32(wp.wcr, 5, 8, 0xff); + } else { + return -ENOBUFS; + } + } + + g_array_append_val(hw_watchpoints, wp); + return 0; +} + + +static bool check_watchpoint_in_range(int i, target_ulong addr) +{ + HWWatchpoint *wp = get_hw_wp(i); + uint64_t addr_top, addr_bottom = wp->wvr; + int bas = extract32(wp->wcr, 5, 8); + int mask = extract32(wp->wcr, 24, 4); + + if (mask) { + addr_top = addr_bottom + (1 << mask); + } else { + /* BAS must be contiguous but can offset against the base + * address in DBGWVR */ + addr_bottom = addr_bottom + ctz32(bas); + addr_top = addr_bottom + clo32(bas); + } + + if (addr >= addr_bottom && addr <= addr_top) { + return true; + } + + return false; +} + +/** + * delete_hw_watchpoint() + * @addr: address of breakpoint + * + * Delete a breakpoint and shuffle any above down + */ + +static int delete_hw_watchpoint(target_ulong addr, + target_ulong len, int type) +{ + int i; + for (i = 0; i < cur_hw_wps; i++) { + if (check_watchpoint_in_range(i, addr)) { + g_array_remove_index(hw_watchpoints, i); + return 0; + } + } + return -ENOENT; +} + + +int kvm_arch_insert_hw_breakpoint(target_ulong addr, + target_ulong len, int type) +{ + switch (type) { + case GDB_BREAKPOINT_HW: + return insert_hw_breakpoint(addr); + break; + case GDB_WATCHPOINT_READ: + case GDB_WATCHPOINT_WRITE: + case GDB_WATCHPOINT_ACCESS: + return insert_hw_watchpoint(addr, len, type); + default: + return -ENOSYS; + } +} + +int kvm_arch_remove_hw_breakpoint(target_ulong addr, + target_ulong len, int type) +{ + switch (type) { + case GDB_BREAKPOINT_HW: + return delete_hw_breakpoint(addr); + break; + case GDB_WATCHPOINT_READ: + case GDB_WATCHPOINT_WRITE: + case GDB_WATCHPOINT_ACCESS: + return delete_hw_watchpoint(addr, len, type); + default: + return -ENOSYS; + } +} + + +void kvm_arch_remove_all_hw_breakpoints(void) +{ + if (cur_hw_wps > 0) { + g_array_remove_range(hw_watchpoints, 0, cur_hw_wps); + } + if (cur_hw_bps > 0) { + g_array_remove_range(hw_breakpoints, 0, cur_hw_bps); + } +} + +void kvm_arm_copy_hw_debug_data(struct kvm_guest_debug_arch *ptr) +{ + int i; + memset(ptr, 0, sizeof(struct kvm_guest_debug_arch)); + + for (i = 0; i < max_hw_wps; i++) { + HWWatchpoint *wp = get_hw_wp(i); + ptr->dbg_wcr[i] = wp->wcr; + ptr->dbg_wvr[i] = wp->wvr; + } + for (i = 0; i < max_hw_bps; i++) { + HWBreakpoint *bp = get_hw_bp(i); + ptr->dbg_bcr[i] = bp->bcr; + ptr->dbg_bvr[i] = bp->bvr; + } +} + +bool kvm_arm_hw_debug_active(CPUState *cs) +{ + return ((cur_hw_wps > 0) || (cur_hw_bps > 0)); +} + +static bool find_hw_breakpoint(CPUState *cpu, target_ulong pc) +{ + int i; + + for (i = 0; i < cur_hw_bps; i++) { + HWBreakpoint *bp = get_hw_bp(i); + if (bp->bvr == pc) { + return true; + } + } + return false; +} + +static CPUWatchpoint *find_hw_watchpoint(CPUState *cpu, target_ulong addr) +{ + int i; + + for (i = 0; i < cur_hw_wps; i++) { + if (check_watchpoint_in_range(i, addr)) { + return &get_hw_wp(i)->details; + } + } + return NULL; +} + + static inline void set_feature(uint64_t *features, int feature) { *features |= 1ULL << feature; @@ -546,6 +889,20 @@ bool kvm_arm_handle_debug(CPUState *cs, struct kvm_debug_exit_arch *debug_exit) return true; } break; + case EC_BREAKPOINT: + if (find_hw_breakpoint(cs, env->pc)) { + return true; + } + break; + case EC_WATCHPOINT: + { + CPUWatchpoint *wp = find_hw_watchpoint(cs, debug_exit->far); + if (wp) { + cs->watchpoint_hit = wp; + return true; + } + break; + } default: error_report("%s: unhandled debug exit (%"PRIx32", %"PRIx64")\n", __func__, debug_exit->hsr, env->pc); |