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/*
* Event entry/exit for Hexagon
*
* Copyright (c) 2010-2011, The Linux Foundation. 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
P0 = cmp.eq(R24, #0);
if P0 jump return_from_syscall
R0 = R25;
callr R24
jump return_from_syscall
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