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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /arch/x86/lib/insn.c | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
Diffstat (limited to 'arch/x86/lib/insn.c')
-rw-r--r-- | arch/x86/lib/insn.c | 755 |
1 files changed, 755 insertions, 0 deletions
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c new file mode 100644 index 000000000..55e371cc6 --- /dev/null +++ b/arch/x86/lib/insn.c @@ -0,0 +1,755 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * x86 instruction analysis + * + * Copyright (C) IBM Corporation, 2002, 2004, 2009 + */ + +#include <linux/kernel.h> +#ifdef __KERNEL__ +#include <linux/string.h> +#else +#include <string.h> +#endif +#include <asm/inat.h> /*__ignore_sync_check__ */ +#include <asm/insn.h> /* __ignore_sync_check__ */ +#include <asm/unaligned.h> /* __ignore_sync_check__ */ + +#include <linux/errno.h> +#include <linux/kconfig.h> + +#include <asm/emulate_prefix.h> /* __ignore_sync_check__ */ + +#define leXX_to_cpu(t, r) \ +({ \ + __typeof__(t) v; \ + switch (sizeof(t)) { \ + case 4: v = le32_to_cpu(r); break; \ + case 2: v = le16_to_cpu(r); break; \ + case 1: v = r; break; \ + default: \ + BUILD_BUG(); break; \ + } \ + v; \ +}) + +/* Verify next sizeof(t) bytes can be on the same instruction */ +#define validate_next(t, insn, n) \ + ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) + +#define __get_next(t, insn) \ + ({ t r = get_unaligned((t *)(insn)->next_byte); (insn)->next_byte += sizeof(t); leXX_to_cpu(t, r); }) + +#define __peek_nbyte_next(t, insn, n) \ + ({ t r = get_unaligned((t *)(insn)->next_byte + n); leXX_to_cpu(t, r); }) + +#define get_next(t, insn) \ + ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); }) + +#define peek_nbyte_next(t, insn, n) \ + ({ if (unlikely(!validate_next(t, insn, n))) goto err_out; __peek_nbyte_next(t, insn, n); }) + +#define peek_next(t, insn) peek_nbyte_next(t, insn, 0) + +/** + * insn_init() - initialize struct insn + * @insn: &struct insn to be initialized + * @kaddr: address (in kernel memory) of instruction (or copy thereof) + * @buf_len: length of the insn buffer at @kaddr + * @x86_64: !0 for 64-bit kernel or 64-bit app + */ +void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64) +{ + /* + * Instructions longer than MAX_INSN_SIZE (15 bytes) are invalid + * even if the input buffer is long enough to hold them. + */ + if (buf_len > MAX_INSN_SIZE) + buf_len = MAX_INSN_SIZE; + + memset(insn, 0, sizeof(*insn)); + insn->kaddr = kaddr; + insn->end_kaddr = kaddr + buf_len; + insn->next_byte = kaddr; + insn->x86_64 = x86_64 ? 1 : 0; + insn->opnd_bytes = 4; + if (x86_64) + insn->addr_bytes = 8; + else + insn->addr_bytes = 4; +} + +static const insn_byte_t xen_prefix[] = { __XEN_EMULATE_PREFIX }; +static const insn_byte_t kvm_prefix[] = { __KVM_EMULATE_PREFIX }; + +static int __insn_get_emulate_prefix(struct insn *insn, + const insn_byte_t *prefix, size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) { + if (peek_nbyte_next(insn_byte_t, insn, i) != prefix[i]) + goto err_out; + } + + insn->emulate_prefix_size = len; + insn->next_byte += len; + + return 1; + +err_out: + return 0; +} + +static void insn_get_emulate_prefix(struct insn *insn) +{ + if (__insn_get_emulate_prefix(insn, xen_prefix, sizeof(xen_prefix))) + return; + + __insn_get_emulate_prefix(insn, kvm_prefix, sizeof(kvm_prefix)); +} + +/** + * insn_get_prefixes - scan x86 instruction prefix bytes + * @insn: &struct insn containing instruction + * + * Populates the @insn->prefixes bitmap, and updates @insn->next_byte + * to point to the (first) opcode. No effect if @insn->prefixes.got + * is already set. + * + * * Returns: + * 0: on success + * < 0: on error + */ +int insn_get_prefixes(struct insn *insn) +{ + struct insn_field *prefixes = &insn->prefixes; + insn_attr_t attr; + insn_byte_t b, lb; + int i, nb; + + if (prefixes->got) + return 0; + + insn_get_emulate_prefix(insn); + + nb = 0; + lb = 0; + b = peek_next(insn_byte_t, insn); + attr = inat_get_opcode_attribute(b); + while (inat_is_legacy_prefix(attr)) { + /* Skip if same prefix */ + for (i = 0; i < nb; i++) + if (prefixes->bytes[i] == b) + goto found; + if (nb == 4) + /* Invalid instruction */ + break; + prefixes->bytes[nb++] = b; + if (inat_is_address_size_prefix(attr)) { + /* address size switches 2/4 or 4/8 */ + if (insn->x86_64) + insn->addr_bytes ^= 12; + else + insn->addr_bytes ^= 6; + } else if (inat_is_operand_size_prefix(attr)) { + /* oprand size switches 2/4 */ + insn->opnd_bytes ^= 6; + } +found: + prefixes->nbytes++; + insn->next_byte++; + lb = b; + b = peek_next(insn_byte_t, insn); + attr = inat_get_opcode_attribute(b); + } + /* Set the last prefix */ + if (lb && lb != insn->prefixes.bytes[3]) { + if (unlikely(insn->prefixes.bytes[3])) { + /* Swap the last prefix */ + b = insn->prefixes.bytes[3]; + for (i = 0; i < nb; i++) + if (prefixes->bytes[i] == lb) + insn_set_byte(prefixes, i, b); + } + insn_set_byte(&insn->prefixes, 3, lb); + } + + /* Decode REX prefix */ + if (insn->x86_64) { + b = peek_next(insn_byte_t, insn); + attr = inat_get_opcode_attribute(b); + if (inat_is_rex_prefix(attr)) { + insn_field_set(&insn->rex_prefix, b, 1); + insn->next_byte++; + if (X86_REX_W(b)) + /* REX.W overrides opnd_size */ + insn->opnd_bytes = 8; + } + } + insn->rex_prefix.got = 1; + + /* Decode VEX prefix */ + b = peek_next(insn_byte_t, insn); + attr = inat_get_opcode_attribute(b); + if (inat_is_vex_prefix(attr)) { + insn_byte_t b2 = peek_nbyte_next(insn_byte_t, insn, 1); + if (!insn->x86_64) { + /* + * In 32-bits mode, if the [7:6] bits (mod bits of + * ModRM) on the second byte are not 11b, it is + * LDS or LES or BOUND. + */ + if (X86_MODRM_MOD(b2) != 3) + goto vex_end; + } + insn_set_byte(&insn->vex_prefix, 0, b); + insn_set_byte(&insn->vex_prefix, 1, b2); + if (inat_is_evex_prefix(attr)) { + b2 = peek_nbyte_next(insn_byte_t, insn, 2); + insn_set_byte(&insn->vex_prefix, 2, b2); + b2 = peek_nbyte_next(insn_byte_t, insn, 3); + insn_set_byte(&insn->vex_prefix, 3, b2); + insn->vex_prefix.nbytes = 4; + insn->next_byte += 4; + if (insn->x86_64 && X86_VEX_W(b2)) + /* VEX.W overrides opnd_size */ + insn->opnd_bytes = 8; + } else if (inat_is_vex3_prefix(attr)) { + b2 = peek_nbyte_next(insn_byte_t, insn, 2); + insn_set_byte(&insn->vex_prefix, 2, b2); + insn->vex_prefix.nbytes = 3; + insn->next_byte += 3; + if (insn->x86_64 && X86_VEX_W(b2)) + /* VEX.W overrides opnd_size */ + insn->opnd_bytes = 8; + } else { + /* + * For VEX2, fake VEX3-like byte#2. + * Makes it easier to decode vex.W, vex.vvvv, + * vex.L and vex.pp. Masking with 0x7f sets vex.W == 0. + */ + insn_set_byte(&insn->vex_prefix, 2, b2 & 0x7f); + insn->vex_prefix.nbytes = 2; + insn->next_byte += 2; + } + } +vex_end: + insn->vex_prefix.got = 1; + + prefixes->got = 1; + + return 0; + +err_out: + return -ENODATA; +} + +/** + * insn_get_opcode - collect opcode(s) + * @insn: &struct insn containing instruction + * + * Populates @insn->opcode, updates @insn->next_byte to point past the + * opcode byte(s), and set @insn->attr (except for groups). + * If necessary, first collects any preceding (prefix) bytes. + * Sets @insn->opcode.value = opcode1. No effect if @insn->opcode.got + * is already 1. + * + * Returns: + * 0: on success + * < 0: on error + */ +int insn_get_opcode(struct insn *insn) +{ + struct insn_field *opcode = &insn->opcode; + int pfx_id, ret; + insn_byte_t op; + + if (opcode->got) + return 0; + + if (!insn->prefixes.got) { + ret = insn_get_prefixes(insn); + if (ret) + return ret; + } + + /* Get first opcode */ + op = get_next(insn_byte_t, insn); + insn_set_byte(opcode, 0, op); + opcode->nbytes = 1; + + /* Check if there is VEX prefix or not */ + if (insn_is_avx(insn)) { + insn_byte_t m, p; + m = insn_vex_m_bits(insn); + p = insn_vex_p_bits(insn); + insn->attr = inat_get_avx_attribute(op, m, p); + if ((inat_must_evex(insn->attr) && !insn_is_evex(insn)) || + (!inat_accept_vex(insn->attr) && + !inat_is_group(insn->attr))) { + /* This instruction is bad */ + insn->attr = 0; + return -EINVAL; + } + /* VEX has only 1 byte for opcode */ + goto end; + } + + insn->attr = inat_get_opcode_attribute(op); + while (inat_is_escape(insn->attr)) { + /* Get escaped opcode */ + op = get_next(insn_byte_t, insn); + opcode->bytes[opcode->nbytes++] = op; + pfx_id = insn_last_prefix_id(insn); + insn->attr = inat_get_escape_attribute(op, pfx_id, insn->attr); + } + + if (inat_must_vex(insn->attr)) { + /* This instruction is bad */ + insn->attr = 0; + return -EINVAL; + } +end: + opcode->got = 1; + return 0; + +err_out: + return -ENODATA; +} + +/** + * insn_get_modrm - collect ModRM byte, if any + * @insn: &struct insn containing instruction + * + * Populates @insn->modrm and updates @insn->next_byte to point past the + * ModRM byte, if any. If necessary, first collects the preceding bytes + * (prefixes and opcode(s)). No effect if @insn->modrm.got is already 1. + * + * Returns: + * 0: on success + * < 0: on error + */ +int insn_get_modrm(struct insn *insn) +{ + struct insn_field *modrm = &insn->modrm; + insn_byte_t pfx_id, mod; + int ret; + + if (modrm->got) + return 0; + + if (!insn->opcode.got) { + ret = insn_get_opcode(insn); + if (ret) + return ret; + } + + if (inat_has_modrm(insn->attr)) { + mod = get_next(insn_byte_t, insn); + insn_field_set(modrm, mod, 1); + if (inat_is_group(insn->attr)) { + pfx_id = insn_last_prefix_id(insn); + insn->attr = inat_get_group_attribute(mod, pfx_id, + insn->attr); + if (insn_is_avx(insn) && !inat_accept_vex(insn->attr)) { + /* Bad insn */ + insn->attr = 0; + return -EINVAL; + } + } + } + + if (insn->x86_64 && inat_is_force64(insn->attr)) + insn->opnd_bytes = 8; + + modrm->got = 1; + return 0; + +err_out: + return -ENODATA; +} + + +/** + * insn_rip_relative() - Does instruction use RIP-relative addressing mode? + * @insn: &struct insn containing instruction + * + * If necessary, first collects the instruction up to and including the + * ModRM byte. No effect if @insn->x86_64 is 0. + */ +int insn_rip_relative(struct insn *insn) +{ + struct insn_field *modrm = &insn->modrm; + int ret; + + if (!insn->x86_64) + return 0; + + if (!modrm->got) { + ret = insn_get_modrm(insn); + if (ret) + return 0; + } + /* + * For rip-relative instructions, the mod field (top 2 bits) + * is zero and the r/m field (bottom 3 bits) is 0x5. + */ + return (modrm->nbytes && (modrm->bytes[0] & 0xc7) == 0x5); +} + +/** + * insn_get_sib() - Get the SIB byte of instruction + * @insn: &struct insn containing instruction + * + * If necessary, first collects the instruction up to and including the + * ModRM byte. + * + * Returns: + * 0: if decoding succeeded + * < 0: otherwise. + */ +int insn_get_sib(struct insn *insn) +{ + insn_byte_t modrm; + int ret; + + if (insn->sib.got) + return 0; + + if (!insn->modrm.got) { + ret = insn_get_modrm(insn); + if (ret) + return ret; + } + + if (insn->modrm.nbytes) { + modrm = insn->modrm.bytes[0]; + if (insn->addr_bytes != 2 && + X86_MODRM_MOD(modrm) != 3 && X86_MODRM_RM(modrm) == 4) { + insn_field_set(&insn->sib, + get_next(insn_byte_t, insn), 1); + } + } + insn->sib.got = 1; + + return 0; + +err_out: + return -ENODATA; +} + + +/** + * insn_get_displacement() - Get the displacement of instruction + * @insn: &struct insn containing instruction + * + * If necessary, first collects the instruction up to and including the + * SIB byte. + * Displacement value is sign-expanded. + * + * * Returns: + * 0: if decoding succeeded + * < 0: otherwise. + */ +int insn_get_displacement(struct insn *insn) +{ + insn_byte_t mod, rm, base; + int ret; + + if (insn->displacement.got) + return 0; + + if (!insn->sib.got) { + ret = insn_get_sib(insn); + if (ret) + return ret; + } + + if (insn->modrm.nbytes) { + /* + * Interpreting the modrm byte: + * mod = 00 - no displacement fields (exceptions below) + * mod = 01 - 1-byte displacement field + * mod = 10 - displacement field is 4 bytes, or 2 bytes if + * address size = 2 (0x67 prefix in 32-bit mode) + * mod = 11 - no memory operand + * + * If address size = 2... + * mod = 00, r/m = 110 - displacement field is 2 bytes + * + * If address size != 2... + * mod != 11, r/m = 100 - SIB byte exists + * mod = 00, SIB base = 101 - displacement field is 4 bytes + * mod = 00, r/m = 101 - rip-relative addressing, displacement + * field is 4 bytes + */ + mod = X86_MODRM_MOD(insn->modrm.value); + rm = X86_MODRM_RM(insn->modrm.value); + base = X86_SIB_BASE(insn->sib.value); + if (mod == 3) + goto out; + if (mod == 1) { + insn_field_set(&insn->displacement, + get_next(signed char, insn), 1); + } else if (insn->addr_bytes == 2) { + if ((mod == 0 && rm == 6) || mod == 2) { + insn_field_set(&insn->displacement, + get_next(short, insn), 2); + } + } else { + if ((mod == 0 && rm == 5) || mod == 2 || + (mod == 0 && base == 5)) { + insn_field_set(&insn->displacement, + get_next(int, insn), 4); + } + } + } +out: + insn->displacement.got = 1; + return 0; + +err_out: + return -ENODATA; +} + +/* Decode moffset16/32/64. Return 0 if failed */ +static int __get_moffset(struct insn *insn) +{ + switch (insn->addr_bytes) { + case 2: + insn_field_set(&insn->moffset1, get_next(short, insn), 2); + break; + case 4: + insn_field_set(&insn->moffset1, get_next(int, insn), 4); + break; + case 8: + insn_field_set(&insn->moffset1, get_next(int, insn), 4); + insn_field_set(&insn->moffset2, get_next(int, insn), 4); + break; + default: /* opnd_bytes must be modified manually */ + goto err_out; + } + insn->moffset1.got = insn->moffset2.got = 1; + + return 1; + +err_out: + return 0; +} + +/* Decode imm v32(Iz). Return 0 if failed */ +static int __get_immv32(struct insn *insn) +{ + switch (insn->opnd_bytes) { + case 2: + insn_field_set(&insn->immediate, get_next(short, insn), 2); + break; + case 4: + case 8: + insn_field_set(&insn->immediate, get_next(int, insn), 4); + break; + default: /* opnd_bytes must be modified manually */ + goto err_out; + } + + return 1; + +err_out: + return 0; +} + +/* Decode imm v64(Iv/Ov), Return 0 if failed */ +static int __get_immv(struct insn *insn) +{ + switch (insn->opnd_bytes) { + case 2: + insn_field_set(&insn->immediate1, get_next(short, insn), 2); + break; + case 4: + insn_field_set(&insn->immediate1, get_next(int, insn), 4); + insn->immediate1.nbytes = 4; + break; + case 8: + insn_field_set(&insn->immediate1, get_next(int, insn), 4); + insn_field_set(&insn->immediate2, get_next(int, insn), 4); + break; + default: /* opnd_bytes must be modified manually */ + goto err_out; + } + insn->immediate1.got = insn->immediate2.got = 1; + + return 1; +err_out: + return 0; +} + +/* Decode ptr16:16/32(Ap) */ +static int __get_immptr(struct insn *insn) +{ + switch (insn->opnd_bytes) { + case 2: + insn_field_set(&insn->immediate1, get_next(short, insn), 2); + break; + case 4: + insn_field_set(&insn->immediate1, get_next(int, insn), 4); + break; + case 8: + /* ptr16:64 is not exist (no segment) */ + return 0; + default: /* opnd_bytes must be modified manually */ + goto err_out; + } + insn_field_set(&insn->immediate2, get_next(unsigned short, insn), 2); + insn->immediate1.got = insn->immediate2.got = 1; + + return 1; +err_out: + return 0; +} + +/** + * insn_get_immediate() - Get the immediate in an instruction + * @insn: &struct insn containing instruction + * + * If necessary, first collects the instruction up to and including the + * displacement bytes. + * Basically, most of immediates are sign-expanded. Unsigned-value can be + * computed by bit masking with ((1 << (nbytes * 8)) - 1) + * + * Returns: + * 0: on success + * < 0: on error + */ +int insn_get_immediate(struct insn *insn) +{ + int ret; + + if (insn->immediate.got) + return 0; + + if (!insn->displacement.got) { + ret = insn_get_displacement(insn); + if (ret) + return ret; + } + + if (inat_has_moffset(insn->attr)) { + if (!__get_moffset(insn)) + goto err_out; + goto done; + } + + if (!inat_has_immediate(insn->attr)) + /* no immediates */ + goto done; + + switch (inat_immediate_size(insn->attr)) { + case INAT_IMM_BYTE: + insn_field_set(&insn->immediate, get_next(signed char, insn), 1); + break; + case INAT_IMM_WORD: + insn_field_set(&insn->immediate, get_next(short, insn), 2); + break; + case INAT_IMM_DWORD: + insn_field_set(&insn->immediate, get_next(int, insn), 4); + break; + case INAT_IMM_QWORD: + insn_field_set(&insn->immediate1, get_next(int, insn), 4); + insn_field_set(&insn->immediate2, get_next(int, insn), 4); + break; + case INAT_IMM_PTR: + if (!__get_immptr(insn)) + goto err_out; + break; + case INAT_IMM_VWORD32: + if (!__get_immv32(insn)) + goto err_out; + break; + case INAT_IMM_VWORD: + if (!__get_immv(insn)) + goto err_out; + break; + default: + /* Here, insn must have an immediate, but failed */ + goto err_out; + } + if (inat_has_second_immediate(insn->attr)) { + insn_field_set(&insn->immediate2, get_next(signed char, insn), 1); + } +done: + insn->immediate.got = 1; + return 0; + +err_out: + return -ENODATA; +} + +/** + * insn_get_length() - Get the length of instruction + * @insn: &struct insn containing instruction + * + * If necessary, first collects the instruction up to and including the + * immediates bytes. + * + * Returns: + * - 0 on success + * - < 0 on error +*/ +int insn_get_length(struct insn *insn) +{ + int ret; + + if (insn->length) + return 0; + + if (!insn->immediate.got) { + ret = insn_get_immediate(insn); + if (ret) + return ret; + } + + insn->length = (unsigned char)((unsigned long)insn->next_byte + - (unsigned long)insn->kaddr); + + return 0; +} + +/* Ensure this instruction is decoded completely */ +static inline int insn_complete(struct insn *insn) +{ + return insn->opcode.got && insn->modrm.got && insn->sib.got && + insn->displacement.got && insn->immediate.got; +} + +/** + * insn_decode() - Decode an x86 instruction + * @insn: &struct insn to be initialized + * @kaddr: address (in kernel memory) of instruction (or copy thereof) + * @buf_len: length of the insn buffer at @kaddr + * @m: insn mode, see enum insn_mode + * + * Returns: + * 0: if decoding succeeded + * < 0: otherwise. + */ +int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m) +{ + int ret; + +/* #define INSN_MODE_KERN -1 __ignore_sync_check__ mode is only valid in the kernel */ + + if (m == INSN_MODE_KERN) + insn_init(insn, kaddr, buf_len, IS_ENABLED(CONFIG_X86_64)); + else + insn_init(insn, kaddr, buf_len, m == INSN_MODE_64); + + ret = insn_get_length(insn); + if (ret) + return ret; + + if (insn_complete(insn)) + return 0; + + return -EINVAL; +} |