aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/kernel/entry-header.S
diff options
context:
space:
mode:
authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /arch/arm/kernel/entry-header.S
downloadlinux-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/arm/kernel/entry-header.S')
-rw-r--r--arch/arm/kernel/entry-header.S467
1 files changed, 467 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-header.S b/arch/arm/kernel/entry-header.S
new file mode 100644
index 000000000..99411fa91
--- /dev/null
+++ b/arch/arm/kernel/entry-header.S
@@ -0,0 +1,467 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/init.h>
+#include <linux/linkage.h>
+
+#include <asm/assembler.h>
+#include <asm/asm-offsets.h>
+#include <asm/errno.h>
+#include <asm/thread_info.h>
+#include <asm/uaccess-asm.h>
+#include <asm/v7m.h>
+
+@ Bad Abort numbers
+@ -----------------
+@
+#define BAD_PREFETCH 0
+#define BAD_DATA 1
+#define BAD_ADDREXCPTN 2
+#define BAD_IRQ 3
+#define BAD_UNDEFINSTR 4
+
+@
+@ Most of the stack format comes from struct pt_regs, but with
+@ the addition of 8 bytes for storing syscall args 5 and 6.
+@ This _must_ remain a multiple of 8 for EABI.
+@
+#define S_OFF 8
+
+/*
+ * The SWI code relies on the fact that R0 is at the bottom of the stack
+ * (due to slow/fast restore user regs).
+ */
+#if S_R0 != 0
+#error "Please fix"
+#endif
+
+ .macro zero_fp
+#ifdef CONFIG_FRAME_POINTER
+ mov fp, #0
+#endif
+ .endm
+
+#ifdef CONFIG_ALIGNMENT_TRAP
+#define ATRAP(x...) x
+#else
+#define ATRAP(x...)
+#endif
+
+ .macro alignment_trap, rtmp1, rtmp2, label
+#ifdef CONFIG_ALIGNMENT_TRAP
+ mrc p15, 0, \rtmp2, c1, c0, 0
+ ldr_va \rtmp1, \label
+ teq \rtmp1, \rtmp2
+ mcrne p15, 0, \rtmp1, c1, c0, 0
+#endif
+ .endm
+
+#ifdef CONFIG_CPU_V7M
+/*
+ * ARMv7-M exception entry/exit macros.
+ *
+ * xPSR, ReturnAddress(), LR (R14), R12, R3, R2, R1, and R0 are
+ * automatically saved on the current stack (32 words) before
+ * switching to the exception stack (SP_main).
+ *
+ * If exception is taken while in user mode, SP_main is
+ * empty. Otherwise, SP_main is aligned to 64 bit automatically
+ * (CCR.STKALIGN set).
+ *
+ * Linux assumes that the interrupts are disabled when entering an
+ * exception handler and it may BUG if this is not the case. Interrupts
+ * are disabled during entry and reenabled in the exit macro.
+ *
+ * v7m_exception_slow_exit is used when returning from SVC or PendSV.
+ * When returning to kernel mode, we don't return from exception.
+ */
+ .macro v7m_exception_entry
+ @ determine the location of the registers saved by the core during
+ @ exception entry. Depending on the mode the cpu was in when the
+ @ exception happend that is either on the main or the process stack.
+ @ Bit 2 of EXC_RETURN stored in the lr register specifies which stack
+ @ was used.
+ tst lr, #EXC_RET_STACK_MASK
+ mrsne r12, psp
+ moveq r12, sp
+
+ @ we cannot rely on r0-r3 and r12 matching the value saved in the
+ @ exception frame because of tail-chaining. So these have to be
+ @ reloaded.
+ ldmia r12!, {r0-r3}
+
+ @ Linux expects to have irqs off. Do it here before taking stack space
+ cpsid i
+
+ sub sp, #PT_REGS_SIZE-S_IP
+ stmdb sp!, {r0-r11}
+
+ @ load saved r12, lr, return address and xPSR.
+ @ r0-r7 are used for signals and never touched from now on. Clobbering
+ @ r8-r12 is OK.
+ mov r9, r12
+ ldmia r9!, {r8, r10-r12}
+
+ @ calculate the original stack pointer value.
+ @ r9 currently points to the memory location just above the auto saved
+ @ xPSR.
+ @ The cpu might automatically 8-byte align the stack. Bit 9
+ @ of the saved xPSR specifies if stack aligning took place. In this case
+ @ another 32-bit value is included in the stack.
+
+ tst r12, V7M_xPSR_FRAMEPTRALIGN
+ addne r9, r9, #4
+
+ @ store saved r12 using str to have a register to hold the base for stm
+ str r8, [sp, #S_IP]
+ add r8, sp, #S_SP
+ @ store r13-r15, xPSR
+ stmia r8!, {r9-r12}
+ @ store old_r0
+ str r0, [r8]
+ .endm
+
+ /*
+ * PENDSV and SVCALL are configured to have the same exception
+ * priorities. As a kernel thread runs at SVCALL execution priority it
+ * can never be preempted and so we will never have to return to a
+ * kernel thread here.
+ */
+ .macro v7m_exception_slow_exit ret_r0
+ cpsid i
+ ldr lr, =exc_ret
+ ldr lr, [lr]
+
+ @ read original r12, sp, lr, pc and xPSR
+ add r12, sp, #S_IP
+ ldmia r12, {r1-r5}
+
+ @ an exception frame is always 8-byte aligned. To tell the hardware if
+ @ the sp to be restored is aligned or not set bit 9 of the saved xPSR
+ @ accordingly.
+ tst r2, #4
+ subne r2, r2, #4
+ orrne r5, V7M_xPSR_FRAMEPTRALIGN
+ biceq r5, V7M_xPSR_FRAMEPTRALIGN
+
+ @ ensure bit 0 is cleared in the PC, otherwise behaviour is
+ @ unpredictable
+ bic r4, #1
+
+ @ write basic exception frame
+ stmdb r2!, {r1, r3-r5}
+ ldmia sp, {r1, r3-r5}
+ .if \ret_r0
+ stmdb r2!, {r0, r3-r5}
+ .else
+ stmdb r2!, {r1, r3-r5}
+ .endif
+
+ @ restore process sp
+ msr psp, r2
+
+ @ restore original r4-r11
+ ldmia sp!, {r0-r11}
+
+ @ restore main sp
+ add sp, sp, #PT_REGS_SIZE-S_IP
+
+ cpsie i
+ bx lr
+ .endm
+#endif /* CONFIG_CPU_V7M */
+
+ @
+ @ Store/load the USER SP and LR registers by switching to the SYS
+ @ mode. Useful in Thumb-2 mode where "stm/ldm rd, {sp, lr}^" is not
+ @ available. Should only be called from SVC mode
+ @
+ .macro store_user_sp_lr, rd, rtemp, offset = 0
+ mrs \rtemp, cpsr
+ eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
+ msr cpsr_c, \rtemp @ switch to the SYS mode
+
+ str sp, [\rd, #\offset] @ save sp_usr
+ str lr, [\rd, #\offset + 4] @ save lr_usr
+
+ eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
+ msr cpsr_c, \rtemp @ switch back to the SVC mode
+ .endm
+
+ .macro load_user_sp_lr, rd, rtemp, offset = 0
+ mrs \rtemp, cpsr
+ eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
+ msr cpsr_c, \rtemp @ switch to the SYS mode
+
+ ldr sp, [\rd, #\offset] @ load sp_usr
+ ldr lr, [\rd, #\offset + 4] @ load lr_usr
+
+ eor \rtemp, \rtemp, #(SVC_MODE ^ SYSTEM_MODE)
+ msr cpsr_c, \rtemp @ switch back to the SVC mode
+ .endm
+
+
+ .macro svc_exit, rpsr, irq = 0
+ .if \irq != 0
+ @ IRQs already off
+#ifdef CONFIG_TRACE_IRQFLAGS
+ @ The parent context IRQs must have been enabled to get here in
+ @ the first place, so there's no point checking the PSR I bit.
+ bl trace_hardirqs_on
+#endif
+ .else
+ @ IRQs off again before pulling preserved data off the stack
+ disable_irq_notrace
+#ifdef CONFIG_TRACE_IRQFLAGS
+ tst \rpsr, #PSR_I_BIT
+ bleq trace_hardirqs_on
+ tst \rpsr, #PSR_I_BIT
+ blne trace_hardirqs_off
+#endif
+ .endif
+ uaccess_exit tsk, r0, r1
+
+#ifndef CONFIG_THUMB2_KERNEL
+ @ ARM mode SVC restore
+ msr spsr_cxsf, \rpsr
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ sub r0, sp, #4 @ uninhabited address
+ strex r1, r2, [r0] @ clear the exclusive monitor
+#endif
+ ldmia sp, {r0 - pc}^ @ load r0 - pc, cpsr
+#else
+ @ Thumb mode SVC restore
+ ldr lr, [sp, #S_SP] @ top of the stack
+ ldrd r0, r1, [sp, #S_LR] @ calling lr and pc
+
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ strex r2, r1, [sp, #S_LR] @ clear the exclusive monitor
+
+ stmdb lr!, {r0, r1, \rpsr} @ calling lr and rfe context
+ ldmia sp, {r0 - r12}
+ mov sp, lr
+ ldr lr, [sp], #4
+ rfeia sp!
+#endif
+ .endm
+
+ @
+ @ svc_exit_via_fiq - like svc_exit but switches to FIQ mode before exit
+ @
+ @ This macro acts in a similar manner to svc_exit but switches to FIQ
+ @ mode to restore the final part of the register state.
+ @
+ @ We cannot use the normal svc_exit procedure because that would
+ @ clobber spsr_svc (FIQ could be delivered during the first few
+ @ instructions of vector_swi meaning its contents have not been
+ @ saved anywhere).
+ @
+ @ Note that, unlike svc_exit, this macro also does not allow a caller
+ @ supplied rpsr. This is because the FIQ exceptions are not re-entrant
+ @ and the handlers cannot call into the scheduler (meaning the value
+ @ on the stack remains correct).
+ @
+ .macro svc_exit_via_fiq
+ uaccess_exit tsk, r0, r1
+#ifndef CONFIG_THUMB2_KERNEL
+ @ ARM mode restore
+ mov r0, sp
+ ldmib r0, {r1 - r14} @ abort is deadly from here onward (it will
+ @ clobber state restored below)
+ msr cpsr_c, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT
+ add r8, r0, #S_PC
+ ldr r9, [r0, #S_PSR]
+ msr spsr_cxsf, r9
+ ldr r0, [r0, #S_R0]
+ ldmia r8, {pc}^
+#else
+ @ Thumb mode restore
+ add r0, sp, #S_R2
+ ldr lr, [sp, #S_LR]
+ ldr sp, [sp, #S_SP] @ abort is deadly from here onward (it will
+ @ clobber state restored below)
+ ldmia r0, {r2 - r12}
+ mov r1, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT
+ msr cpsr_c, r1
+ sub r0, #S_R2
+ add r8, r0, #S_PC
+ ldmia r0, {r0 - r1}
+ rfeia r8
+#endif
+ .endm
+
+
+ .macro restore_user_regs, fast = 0, offset = 0
+#if defined(CONFIG_CPU_32v6K) && \
+ (!defined(CONFIG_CPU_V6) || defined(CONFIG_SMP))
+#ifdef CONFIG_CPU_V6
+ALT_SMP(nop)
+ALT_UP_B(.L1_\@)
+#endif
+ @ The TLS register update is deferred until return to user space so we
+ @ can use it for other things while running in the kernel
+ mrc p15, 0, r1, c13, c0, 3 @ get current_thread_info pointer
+ ldr r1, [r1, #TI_TP_VALUE]
+ mcr p15, 0, r1, c13, c0, 3 @ set TLS register
+.L1_\@:
+#endif
+
+ uaccess_enable r1, isb=0
+#ifndef CONFIG_THUMB2_KERNEL
+ @ ARM mode restore
+ mov r2, sp
+ ldr r1, [r2, #\offset + S_PSR] @ get calling cpsr
+ ldr lr, [r2, #\offset + S_PC]! @ get pc
+ tst r1, #PSR_I_BIT | 0x0f
+ bne 1f
+ msr spsr_cxsf, r1 @ save in spsr_svc
+#if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_32v6K)
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ strex r1, r2, [r2] @ clear the exclusive monitor
+#endif
+ .if \fast
+ ldmdb r2, {r1 - lr}^ @ get calling r1 - lr
+ .else
+ ldmdb r2, {r0 - lr}^ @ get calling r0 - lr
+ .endif
+ mov r0, r0 @ ARMv5T and earlier require a nop
+ @ after ldm {}^
+ add sp, sp, #\offset + PT_REGS_SIZE
+ movs pc, lr @ return & move spsr_svc into cpsr
+1: bug "Returning to usermode but unexpected PSR bits set?", \@
+#elif defined(CONFIG_CPU_V7M)
+ @ V7M restore.
+ @ Note that we don't need to do clrex here as clearing the local
+ @ monitor is part of the exception entry and exit sequence.
+ .if \offset
+ add sp, #\offset
+ .endif
+ v7m_exception_slow_exit ret_r0 = \fast
+#else
+ @ Thumb mode restore
+ mov r2, sp
+ load_user_sp_lr r2, r3, \offset + S_SP @ calling sp, lr
+ ldr r1, [sp, #\offset + S_PSR] @ get calling cpsr
+ ldr lr, [sp, #\offset + S_PC] @ get pc
+ add sp, sp, #\offset + S_SP
+ tst r1, #PSR_I_BIT | 0x0f
+ bne 1f
+ msr spsr_cxsf, r1 @ save in spsr_svc
+
+ @ We must avoid clrex due to Cortex-A15 erratum #830321
+ strex r1, r2, [sp] @ clear the exclusive monitor
+
+ .if \fast
+ ldmdb sp, {r1 - r12} @ get calling r1 - r12
+ .else
+ ldmdb sp, {r0 - r12} @ get calling r0 - r12
+ .endif
+ add sp, sp, #PT_REGS_SIZE - S_SP
+ movs pc, lr @ return & move spsr_svc into cpsr
+1: bug "Returning to usermode but unexpected PSR bits set?", \@
+#endif /* !CONFIG_THUMB2_KERNEL */
+ .endm
+
+/*
+ * Context tracking subsystem. Used to instrument transitions
+ * between user and kernel mode.
+ */
+ .macro ct_user_exit, save = 1
+#ifdef CONFIG_CONTEXT_TRACKING_USER
+ .if \save
+ stmdb sp!, {r0-r3, ip, lr}
+ bl user_exit_callable
+ ldmia sp!, {r0-r3, ip, lr}
+ .else
+ bl user_exit_callable
+ .endif
+#endif
+ .endm
+
+ .macro ct_user_enter, save = 1
+#ifdef CONFIG_CONTEXT_TRACKING_USER
+ .if \save
+ stmdb sp!, {r0-r3, ip, lr}
+ bl user_enter_callable
+ ldmia sp!, {r0-r3, ip, lr}
+ .else
+ bl user_enter_callable
+ .endif
+#endif
+ .endm
+
+ .macro invoke_syscall, table, nr, tmp, ret, reload=0
+#ifdef CONFIG_CPU_SPECTRE
+ mov \tmp, \nr
+ cmp \tmp, #NR_syscalls @ check upper syscall limit
+ movcs \tmp, #0
+ csdb
+ badr lr, \ret @ return address
+ .if \reload
+ add r1, sp, #S_R0 + S_OFF @ pointer to regs
+ ldmiacc r1, {r0 - r6} @ reload r0-r6
+ stmiacc sp, {r4, r5} @ update stack arguments
+ .endif
+ ldrcc pc, [\table, \tmp, lsl #2] @ call sys_* routine
+#else
+ cmp \nr, #NR_syscalls @ check upper syscall limit
+ badr lr, \ret @ return address
+ .if \reload
+ add r1, sp, #S_R0 + S_OFF @ pointer to regs
+ ldmiacc r1, {r0 - r6} @ reload r0-r6
+ stmiacc sp, {r4, r5} @ update stack arguments
+ .endif
+ ldrcc pc, [\table, \nr, lsl #2] @ call sys_* routine
+#endif
+ .endm
+
+/*
+ * These are the registers used in the syscall handler, and allow us to
+ * have in theory up to 7 arguments to a function - r0 to r6.
+ *
+ * r7 is reserved for the system call number for thumb mode.
+ *
+ * Note that tbl == why is intentional.
+ *
+ * We must set at least "tsk" and "why" when calling ret_with_reschedule.
+ */
+scno .req r7 @ syscall number
+tbl .req r8 @ syscall table pointer
+why .req r8 @ Linux syscall (!= 0)
+tsk .req r9 @ current thread_info
+
+ .macro do_overflow_check, frame_size:req
+#ifdef CONFIG_VMAP_STACK
+ @
+ @ Test whether the SP has overflowed. Task and IRQ stacks are aligned
+ @ so that SP & BIT(THREAD_SIZE_ORDER + PAGE_SHIFT) should always be
+ @ zero.
+ @
+ARM( tst sp, #1 << (THREAD_SIZE_ORDER + PAGE_SHIFT) )
+THUMB( tst r1, #1 << (THREAD_SIZE_ORDER + PAGE_SHIFT) )
+THUMB( it ne )
+ bne .Lstack_overflow_check\@
+
+ .pushsection .text
+.Lstack_overflow_check\@:
+ @
+ @ The stack pointer is not pointing to a valid vmap'ed stack, but it
+ @ may be pointing into the linear map instead, which may happen if we
+ @ are already running from the overflow stack. We cannot detect overflow
+ @ in such cases so just carry on.
+ @
+ str ip, [r0, #12] @ Stash IP on the mode stack
+ ldr_va ip, high_memory @ Start of VMALLOC space
+ARM( cmp sp, ip ) @ SP in vmalloc space?
+THUMB( cmp r1, ip )
+THUMB( itt lo )
+ ldrlo ip, [r0, #12] @ Restore IP
+ blo .Lout\@ @ Carry on
+
+THUMB( sub r1, sp, r1 ) @ Restore original R1
+THUMB( sub sp, r1 ) @ Restore original SP
+ add sp, sp, #\frame_size @ Undo svc_entry's SP change
+ b __bad_stack @ Handle VMAP stack overflow
+ .popsection
+.Lout\@:
+#endif
+ .endm