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Diffstat (limited to 'arch/hexagon/kernel/vm_entry.S')
| -rw-r--r-- | arch/hexagon/kernel/vm_entry.S | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/arch/hexagon/kernel/vm_entry.S b/arch/hexagon/kernel/vm_entry.S new file mode 100644 index 0000000..5b99066 --- /dev/null +++ b/arch/hexagon/kernel/vm_entry.S @@ -0,0 +1,269 @@ +/* + * Event entry/exit for Hexagon + * + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include <asm/asm-offsets.h> /* assembly-safer versions of C defines */ +#include <asm/mem-layout.h> /* sigh, except for page_offset */ +#include <asm/hexagon_vm.h> +#include <asm/thread_info.h> + +/* + * Entry into guest-mode Linux under Hexagon Virtual Machine. + * Stack pointer points to event record - build pt_regs on top of it, + * set up a plausible C stack frame, and dispatch to the C handler. + * On return, do vmrte virtual instruction with SP where we started. + * + * VM Spec 0.5 uses a trap to fetch HVM record now. + */ + +/* + * Save full register state, while setting up thread_info struct + * pointer derived from kernel stack pointer in THREADINFO_REG + * register, putting prior thread_info.regs pointer in a callee-save + * register (R24, which had better not ever be assigned to THREADINFO_REG), + * and updating thread_info.regs to point to current stack frame, + * so as to support nested events in kernel mode. + * + * As this is common code, we set the pt_regs system call number + * to -1 for all events. It will be replaced with the system call + * number in the case where we decode a system call (trap0(#1)). + */ + +#define save_pt_regs()\ + memd(R0 + #_PT_R3130) = R31:30; \ + { memw(R0 + #_PT_R2928) = R28; \ + R31 = memw(R0 + #_PT_ER_VMPSP); }\ + { memw(R0 + #(_PT_R2928 + 4)) = R31; \ + R31 = ugp; } \ + { memd(R0 + #_PT_R2726) = R27:26; \ + R30 = gp ; } \ + memd(R0 + #_PT_R2524) = R25:24; \ + memd(R0 + #_PT_R2322) = R23:22; \ + memd(R0 + #_PT_R2120) = R21:20; \ + memd(R0 + #_PT_R1918) = R19:18; \ + memd(R0 + #_PT_R1716) = R17:16; \ + memd(R0 + #_PT_R1514) = R15:14; \ + memd(R0 + #_PT_R1312) = R13:12; \ + { memd(R0 + #_PT_R1110) = R11:10; \ + R15 = lc0; } \ + { memd(R0 + #_PT_R0908) = R9:8; \ + R14 = sa0; } \ + { memd(R0 + #_PT_R0706) = R7:6; \ + R13 = lc1; } \ + { memd(R0 + #_PT_R0504) = R5:4; \ + R12 = sa1; } \ + { memd(R0 + #_PT_UGPGP) = R31:30; \ + R11 = m1; \ + R2.H = #HI(_THREAD_SIZE); } \ + { memd(R0 + #_PT_LC0SA0) = R15:14; \ + R10 = m0; \ + R2.L = #LO(_THREAD_SIZE); } \ + { memd(R0 + #_PT_LC1SA1) = R13:12; \ + R15 = p3:0; \ + R2 = neg(R2); } \ + { memd(R0 + #_PT_M1M0) = R11:10; \ + R14 = usr; \ + R2 = and(R0,R2); } \ + { memd(R0 + #_PT_PREDSUSR) = R15:14; \ + THREADINFO_REG = R2; } \ + { r24 = memw(THREADINFO_REG + #_THREAD_INFO_PT_REGS); \ + memw(THREADINFO_REG + #_THREAD_INFO_PT_REGS) = R0; \ + R2 = #-1; } \ + { memw(R0 + #_PT_SYSCALL_NR) = R2; \ + R30 = #0; } + +/* + * Restore registers and thread_info.regs state. THREADINFO_REG + * is assumed to still be sane, and R24 to have been correctly + * preserved. Don't restore R29 (SP) until later. + */ + +#define restore_pt_regs() \ + { memw(THREADINFO_REG + #_THREAD_INFO_PT_REGS) = R24; \ + R15:14 = memd(R0 + #_PT_PREDSUSR); } \ + { R11:10 = memd(R0 + #_PT_M1M0); \ + p3:0 = R15; } \ + { R13:12 = memd(R0 + #_PT_LC1SA1); \ + usr = R14; } \ + { R15:14 = memd(R0 + #_PT_LC0SA0); \ + m1 = R11; } \ + { R3:2 = memd(R0 + #_PT_R0302); \ + m0 = R10; } \ + { R5:4 = memd(R0 + #_PT_R0504); \ + lc1 = R13; } \ + { R7:6 = memd(R0 + #_PT_R0706); \ + sa1 = R12; } \ + { R9:8 = memd(R0 + #_PT_R0908); \ + lc0 = R15; } \ + { R11:10 = memd(R0 + #_PT_R1110); \ + sa0 = R14; } \ + { R13:12 = memd(R0 + #_PT_R1312); \ + R15:14 = memd(R0 + #_PT_R1514); } \ + { R17:16 = memd(R0 + #_PT_R1716); \ + R19:18 = memd(R0 + #_PT_R1918); } \ + { R21:20 = memd(R0 + #_PT_R2120); \ + R23:22 = memd(R0 + #_PT_R2322); } \ + { R25:24 = memd(R0 + #_PT_R2524); \ + R27:26 = memd(R0 + #_PT_R2726); } \ + R31:30 = memd(R0 + #_PT_UGPGP); \ + { R28 = memw(R0 + #_PT_R2928); \ + ugp = R31; } \ + { R31:30 = memd(R0 + #_PT_R3130); \ + gp = R30; } + + /* + * Clears off enough space for the rest of pt_regs; evrec is a part + * of pt_regs in HVM mode. Save R0/R1, set handler's address in R1. + * R0 is the address of pt_regs and is the parameter to save_pt_regs. + */ + +/* + * Since the HVM isn't automagically pushing the EVREC onto the stack anymore, + * we'll subract the entire size out and then fill it in ourselves. + * Need to save off R0, R1, R2, R3 immediately. + */ + +#define vm_event_entry(CHandler) \ + { \ + R29 = add(R29, #-(_PT_REGS_SIZE)); \ + memd(R29 + #(_PT_R0100 + -_PT_REGS_SIZE)) = R1:0; \ + } \ + { \ + memd(R29 +#_PT_R0302) = R3:2; \ + } \ + trap1(#HVM_TRAP1_VMGETREGS); \ + { \ + memd(R29 + #_PT_ER_VMEL) = R1:0; \ + R0 = R29; \ + R1.L = #LO(CHandler); \ + } \ + { \ + memd(R29 + #_PT_ER_VMPSP) = R3:2; \ + R1.H = #HI(CHandler); \ + jump event_dispatch; \ + } + +.text + /* + * Do bulk save/restore in one place. + * Adds a jump to dispatch latency, but + * saves hundreds of bytes. + */ + +event_dispatch: + save_pt_regs() + callr r1 + + /* + * If we were in kernel mode, we don't need to check scheduler + * or signals if CONFIG_PREEMPT is not set. If set, then it has + * to jump to a need_resched kind of block. + * BTW, CONFIG_PREEMPT is not supported yet. + */ + +#ifdef CONFIG_PREEMPT + R0 = #VM_INT_DISABLE + trap1(#HVM_TRAP1_VMSETIE) +#endif + + /* "Nested control path" -- if the previous mode was kernel */ + R0 = memw(R29 + #_PT_ER_VMEST); + P0 = tstbit(R0, #HVM_VMEST_UM_SFT); + if !P0 jump restore_all; + /* + * Returning from system call, normally coming back from user mode + */ +return_from_syscall: + /* Disable interrupts while checking TIF */ + R0 = #VM_INT_DISABLE + trap1(#HVM_TRAP1_VMSETIE) + + /* + * Coming back from the C-world, our thread info pointer + * should be in the designated register (usually R19) + */ + R1.L = #LO(_TIF_ALLWORK_MASK) + { + R1.H = #HI(_TIF_ALLWORK_MASK); + R0 = memw(THREADINFO_REG + #_THREAD_INFO_FLAGS); + } + + /* + * Compare against the "return to userspace" _TIF_WORK_MASK + */ + R1 = and(R1,R0); + { P0 = cmp.eq(R1,#0); if (!P0.new) jump:t work_pending;} + jump restore_all; /* we're outta here! */ + +work_pending: + { + P0 = tstbit(R1, #TIF_NEED_RESCHED); + if (!P0.new) jump:nt work_notifysig; + } + call schedule + jump return_from_syscall; /* check for more work */ + +work_notifysig: + /* this is the part that's kind of fuzzy. */ + R1 = and(R0, #(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME)); + P0 = cmp.eq(R1, #0); + if P0 jump restore_all + R1 = R0; /* unsigned long thread_info_flags */ + R0 = R29; /* regs should still be at top of stack */ + call do_notify_resume + +restore_all: + /* Disable interrupts, if they weren't already, before reg restore. */ + R0 = #VM_INT_DISABLE + trap1(#HVM_TRAP1_VMSETIE) + + /* do the setregs here for VM 0.5 */ + /* R29 here should already be pointing at pt_regs */ + R1:0 = memd(R29 + #_PT_ER_VMEL); + R3:2 = memd(R29 + #_PT_ER_VMPSP); + trap1(#HVM_TRAP1_VMSETREGS); + + R0 = R29 + restore_pt_regs() + R1:0 = memd(R29 + #_PT_R0100); + R29 = add(R29, #_PT_REGS_SIZE); + trap1(#HVM_TRAP1_VMRTE) + /* Notreached */ + + .globl _K_enter_genex +_K_enter_genex: + vm_event_entry(do_genex) + + .globl _K_enter_interrupt +_K_enter_interrupt: + vm_event_entry(arch_do_IRQ) + + .globl _K_enter_trap0 +_K_enter_trap0: + vm_event_entry(do_trap0) + + .globl _K_enter_machcheck +_K_enter_machcheck: + vm_event_entry(do_machcheck) + + + .globl ret_from_fork +ret_from_fork: + call schedule_tail + jump return_from_syscall |