rsr a0, sar
s32i a3, a2, PT_AREG3
- s32i a4, a2, PT_AREG4
- s32i a0, a2, PT_AREG5 # store SAR to PT_AREG5
+ s32i a0, a2, PT_SAR
- /* The spill routine might clobber a7, a11, and a15. */
+ /* The spill routine might clobber a4, a7, a8, a11, a12, and a15. */
+ s32i a4, a2, PT_AREG4
s32i a7, a2, PT_AREG7
+ s32i a8, a2, PT_AREG8
s32i a11, a2, PT_AREG11
+ s32i a12, a2, PT_AREG12
s32i a15, a2, PT_AREG15
- call0 _spill_registers # destroys a3, a4, and SAR
-
- /* Advance PC, restore registers and SAR, and return from exception. */
-
- l32i a3, a2, PT_AREG5
- l32i a4, a2, PT_AREG4
- l32i a0, a2, PT_AREG0
- wsr a3, sar
- l32i a3, a2, PT_AREG3
-
- /* Restore clobbered registers. */
-
- l32i a7, a2, PT_AREG7
- l32i a11, a2, PT_AREG11
- l32i a15, a2, PT_AREG15
-
- movi a2, 0
- rfe
-
-ENDPROC(fast_syscall_spill_registers)
-
-/* Fixup handler.
- *
- * We get here if the spill routine causes an exception, e.g. tlb miss.
- * We basically restore WINDOWBASE and WINDOWSTART to the condition when
- * we entered the spill routine and jump to the user exception handler.
- *
- * a0: value of depc, original value in depc
- * a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE
- * a3: exctable, original value in excsave1
- */
-
-ENTRY(fast_syscall_spill_registers_fixup)
-
- rsr a2, windowbase # get current windowbase (a2 is saved)
- xsr a0, depc # restore depc and a0
- ssl a2 # set shift (32 - WB)
-
- /* We need to make sure the current registers (a0-a3) are preserved.
- * To do this, we simply set the bit for the current window frame
- * in WS, so that the exception handlers save them to the task stack.
- */
-
- xsr a3, excsave1 # get spill-mask
- slli a3, a3, 1 # shift left by one
-
- slli a2, a3, 32-WSBITS
- src a2, a3, a2 # a2 = xxwww1yyxxxwww1yy......
- wsr a2, windowstart # set corrected windowstart
-
- srli a3, a3, 1
- rsr a2, excsave1
- l32i a2, a2, EXC_TABLE_DOUBLE_SAVE # restore a2
- xsr a2, excsave1
- s32i a3, a2, EXC_TABLE_DOUBLE_SAVE # save a3
- l32i a3, a2, EXC_TABLE_PARAM # original WB (in user task)
- xsr a2, excsave1
-
- /* Return to the original (user task) WINDOWBASE.
- * We leave the following frame behind:
- * a0, a1, a2 same
- * a3: trashed (saved in EXC_TABLE_DOUBLE_SAVE)
- * depc: depc (we have to return to that address)
- * excsave_1: exctable
- */
-
- wsr a3, windowbase
- rsync
-
- /* We are now in the original frame when we entered _spill_registers:
- * a0: return address
- * a1: used, stack pointer
- * a2: kernel stack pointer
- * a3: available
- * depc: exception address
- * excsave: exctable
- * Note: This frame might be the same as above.
- */
-
- /* Setup stack pointer. */
-
- addi a2, a2, -PT_USER_SIZE
- s32i a0, a2, PT_AREG0
-
- /* Make sure we return to this fixup handler. */
-
- movi a3, fast_syscall_spill_registers_fixup_return
- s32i a3, a2, PT_DEPC # setup depc
-
- /* Jump to the exception handler. */
-
- rsr a3, excsave1
- rsr a0, exccause
- addx4 a0, a0, a3 # find entry in table
- l32i a0, a0, EXC_TABLE_FAST_USER # load handler
- l32i a3, a3, EXC_TABLE_DOUBLE_SAVE
- jx a0
-
-ENDPROC(fast_syscall_spill_registers_fixup)
-
-ENTRY(fast_syscall_spill_registers_fixup_return)
-
- /* When we return here, all registers have been restored (a2: DEPC) */
-
- wsr a2, depc # exception address
-
- /* Restore fixup handler. */
-
- rsr a2, excsave1
- s32i a3, a2, EXC_TABLE_DOUBLE_SAVE
- movi a3, fast_syscall_spill_registers_fixup
- s32i a3, a2, EXC_TABLE_FIXUP
- rsr a3, windowbase
- s32i a3, a2, EXC_TABLE_PARAM
- l32i a2, a2, EXC_TABLE_KSTK
-
- /* Load WB at the time the exception occurred. */
-
- rsr a3, sar # WB is still in SAR
- neg a3, a3
- wsr a3, windowbase
- rsync
-
- rsr a3, excsave1
- l32i a3, a3, EXC_TABLE_DOUBLE_SAVE
-
- rfde
-
-ENDPROC(fast_syscall_spill_registers_fixup_return)
-
-/*
- * spill all registers.
- *
- * This is not a real function. The following conditions must be met:
- *
- * - must be called with call0.
- * - uses a3, a4 and SAR.
- * - the last 'valid' register of each frame are clobbered.
- * - the caller must have registered a fixup handler
- * (or be inside a critical section)
- * - PS_EXCM must be set (PS_WOE cleared?)
- */
-
-ENTRY(_spill_registers)
-
/*
* Rotate ws so that the current windowbase is at bit 0.
* Assume ws = xxxwww1yy (www1 current window frame).
* Rotate ws right so that a4 = yyxxxwww1.
*/
- rsr a4, windowbase
+ rsr a0, windowbase
rsr a3, windowstart # a3 = xxxwww1yy
- ssr a4 # holds WB
- slli a4, a3, WSBITS
- or a3, a3, a4 # a3 = xxxwww1yyxxxwww1yy
+ ssr a0 # holds WB
+ slli a0, a3, WSBITS
+ or a3, a3, a0 # a3 = xxxwww1yyxxxwww1yy
srl a3, a3 # a3 = 00xxxwww1yyxxxwww1
/* We are done if there are no more than the current register frame. */
extui a3, a3, 1, WSBITS-1 # a3 = 0yyxxxwww
- movi a4, (1 << (WSBITS-1))
+ movi a0, (1 << (WSBITS-1))
_beqz a3, .Lnospill # only one active frame? jump
/* We want 1 at the top, so that we return to the current windowbase */
- or a3, a3, a4 # 1yyxxxwww
+ or a3, a3, a0 # 1yyxxxwww
/* Skip empty frames - get 'oldest' WINDOWSTART-bit. */
wsr a3, windowstart # save shifted windowstart
- neg a4, a3
- and a3, a4, a3 # first bit set from right: 000010000
+ neg a0, a3
+ and a3, a0, a3 # first bit set from right: 000010000
- ffs_ws a4, a3 # a4: shifts to skip empty frames
+ ffs_ws a0, a3 # a0: shifts to skip empty frames
movi a3, WSBITS
- sub a4, a3, a4 # WSBITS-a4:number of 0-bits from right
- ssr a4 # save in SAR for later.
+ sub a0, a3, a0 # WSBITS-a0:number of 0-bits from right
+ ssr a0 # save in SAR for later.
rsr a3, windowbase
- add a3, a3, a4
+ add a3, a3, a0
wsr a3, windowbase
rsync
* we have to save 4,8. or 12 registers.
*/
- _bbsi.l a3, 1, .Lc4
- _bbsi.l a3, 2, .Lc8
-
- /* Special case: we have a call12-frame starting at a4. */
-
- _bbci.l a3, 3, .Lc12 # bit 3 shouldn't be zero! (Jump to Lc12 first)
-
- s32e a4, a1, -16 # a1 is valid with an empty spill area
- l32e a4, a5, -12
- s32e a8, a4, -48
- mov a8, a4
- l32e a4, a1, -16
- j .Lc12c
-
-.Lnospill:
- ret
.Lloop: _bbsi.l a3, 1, .Lc4
_bbci.l a3, 2, .Lc12
s32e a9, a4, -28
s32e a10, a4, -24
s32e a11, a4, -20
-
srli a11, a3, 2 # shift windowbase by 2
rotw 2
_bnei a3, 1, .Lloop
-
-.Lexit: /* Done. Do the final rotation, set WS, and return. */
-
- rotw 1
- rsr a3, windowbase
- ssl a3
- movi a3, 1
- sll a3, a3
- wsr a3, windowstart
- ret
+ j .Lexit
.Lc4: s32e a4, a9, -16
s32e a5, a9, -12
/* 12-register frame (call12) */
- l32e a2, a5, -12
- s32e a8, a2, -48
- mov a8, a2
+ l32e a0, a5, -12
+ s32e a8, a0, -48
+ mov a8, a0
-.Lc12c: s32e a9, a8, -44
+ s32e a9, a8, -44
s32e a10, a8, -40
s32e a11, a8, -36
s32e a12, a8, -32
*/
rotw 1
- mov a5, a13
+ mov a4, a13
rotw -1
- s32e a4, a9, -16
- s32e a5, a9, -12
- s32e a6, a9, -8
- s32e a7, a9, -4
+ s32e a4, a8, -16
+ s32e a5, a8, -12
+ s32e a6, a8, -8
+ s32e a7, a8, -4
rotw 3
_beqi a3, 1, .Lexit
j .Lloop
-.Linvalid_mask:
+.Lexit:
- /* We get here because of an unrecoverable error in the window
- * registers. If we are in user space, we kill the application,
- * however, this condition is unrecoverable in kernel space.
- */
+ /* Done. Do the final rotation and set WS */
+
+ rotw 1
+ rsr a3, windowbase
+ ssl a3
+ movi a3, 1
+ sll a3, a3
+ wsr a3, windowstart
+.Lnospill:
+
+ /* Advance PC, restore registers and SAR, and return from exception. */
+
+ l32i a3, a2, PT_SAR
+ l32i a0, a2, PT_AREG0
+ wsr a3, sar
+ l32i a3, a2, PT_AREG3
- rsr a0, ps
- _bbci.l a0, PS_UM_BIT, 1f
+ /* Restore clobbered registers. */
- /* User space: Setup a dummy frame and kill application.
+ l32i a4, a2, PT_AREG4
+ l32i a7, a2, PT_AREG7
+ l32i a8, a2, PT_AREG8
+ l32i a11, a2, PT_AREG11
+ l32i a12, a2, PT_AREG12
+ l32i a15, a2, PT_AREG15
+
+ movi a2, 0
+ rfe
+
+.Linvalid_mask:
+
+ /* We get here because of an unrecoverable error in the window
+ * registers, so set up a dummy frame and kill the user application.
* Note: We assume EXC_TABLE_KSTK contains a valid stack pointer.
*/
movi a4, do_exit
callx4 a4
-1: /* Kernel space: PANIC! */
+ /* shouldn't return, so panic */
wsr a0, excsave1
movi a0, unrecoverable_exception
callx0 a0 # should not return
1: j 1b
-ENDPROC(_spill_registers)
+
+ENDPROC(fast_syscall_spill_registers)
+
+/* Fixup handler.
+ *
+ * We get here if the spill routine causes an exception, e.g. tlb miss.
+ * We basically restore WINDOWBASE and WINDOWSTART to the condition when
+ * we entered the spill routine and jump to the user exception handler.
+ *
+ * Note that we only need to restore the bits in windowstart that have not
+ * been spilled yet by the _spill_register routine. Luckily, a3 contains a
+ * rotated windowstart with only those bits set for frames that haven't been
+ * spilled yet. Because a3 is rotated such that bit 0 represents the register
+ * frame for the current windowbase - 1, we need to rotate a3 left by the
+ * value of the current windowbase + 1 and move it to windowstart.
+ *
+ * a0: value of depc, original value in depc
+ * a2: trashed, original value in EXC_TABLE_DOUBLE_SAVE
+ * a3: exctable, original value in excsave1
+ */
+
+ENTRY(fast_syscall_spill_registers_fixup)
+
+ rsr a2, windowbase # get current windowbase (a2 is saved)
+ xsr a0, depc # restore depc and a0
+ ssl a2 # set shift (32 - WB)
+
+ /* We need to make sure the current registers (a0-a3) are preserved.
+ * To do this, we simply set the bit for the current window frame
+ * in WS, so that the exception handlers save them to the task stack.
+ *
+ * Note: we use a3 to set the windowbase, so we take a special care
+ * of it, saving it in the original _spill_registers frame across
+ * the exception handler call.
+ */
+
+ xsr a3, excsave1 # get spill-mask
+ slli a3, a3, 1 # shift left by one
+ addi a3, a3, 1 # set the bit for the current window frame
+
+ slli a2, a3, 32-WSBITS
+ src a2, a3, a2 # a2 = xxwww1yyxxxwww1yy......
+ wsr a2, windowstart # set corrected windowstart
+
+ srli a3, a3, 1
+ rsr a2, excsave1
+ l32i a2, a2, EXC_TABLE_DOUBLE_SAVE # restore a2
+ xsr a2, excsave1
+ s32i a3, a2, EXC_TABLE_DOUBLE_SAVE # save a3
+ l32i a3, a2, EXC_TABLE_PARAM # original WB (in user task)
+ xsr a2, excsave1
+
+ /* Return to the original (user task) WINDOWBASE.
+ * We leave the following frame behind:
+ * a0, a1, a2 same
+ * a3: trashed (saved in EXC_TABLE_DOUBLE_SAVE)
+ * depc: depc (we have to return to that address)
+ * excsave_1: exctable
+ */
+
+ wsr a3, windowbase
+ rsync
+
+ /* We are now in the original frame when we entered _spill_registers:
+ * a0: return address
+ * a1: used, stack pointer
+ * a2: kernel stack pointer
+ * a3: available
+ * depc: exception address
+ * excsave: exctable
+ * Note: This frame might be the same as above.
+ */
+
+ /* Setup stack pointer. */
+
+ addi a2, a2, -PT_USER_SIZE
+ s32i a0, a2, PT_AREG0
+
+ /* Make sure we return to this fixup handler. */
+
+ movi a3, fast_syscall_spill_registers_fixup_return
+ s32i a3, a2, PT_DEPC # setup depc
+
+ /* Jump to the exception handler. */
+
+ rsr a3, excsave1
+ rsr a0, exccause
+ addx4 a0, a0, a3 # find entry in table
+ l32i a0, a0, EXC_TABLE_FAST_USER # load handler
+ l32i a3, a3, EXC_TABLE_DOUBLE_SAVE
+ jx a0
+
+ENDPROC(fast_syscall_spill_registers_fixup)
+
+ENTRY(fast_syscall_spill_registers_fixup_return)
+
+ /* When we return here, all registers have been restored (a2: DEPC) */
+
+ wsr a2, depc # exception address
+
+ /* Restore fixup handler. */
+
+ rsr a2, excsave1
+ s32i a3, a2, EXC_TABLE_DOUBLE_SAVE
+ movi a3, fast_syscall_spill_registers_fixup
+ s32i a3, a2, EXC_TABLE_FIXUP
+ rsr a3, windowbase
+ s32i a3, a2, EXC_TABLE_PARAM
+ l32i a2, a2, EXC_TABLE_KSTK
+
+ /* Load WB at the time the exception occurred. */
+
+ rsr a3, sar # WB is still in SAR
+ neg a3, a3
+ wsr a3, windowbase
+ rsync
+
+ rsr a3, excsave1
+ l32i a3, a3, EXC_TABLE_DOUBLE_SAVE
+
+ rfde
+
+ENDPROC(fast_syscall_spill_registers_fixup_return)
#ifdef CONFIG_MMU
/*
ENDPROC(system_call)
+/*
+ * Spill live registers on the kernel stack macro.
+ *
+ * Entry condition: ps.woe is set, ps.excm is cleared
+ * Exit condition: windowstart has single bit set
+ * May clobber: a12, a13
+ */
+ .macro spill_registers_kernel
+
+#if XCHAL_NUM_AREGS > 16
+ call12 1f
+ _j 2f
+ retw
+ .align 4
+1:
+ _entry a1, 48
+ addi a12, a0, 3
+#if XCHAL_NUM_AREGS > 32
+ .rept (XCHAL_NUM_AREGS - 32) / 12
+ _entry a1, 48
+ mov a12, a0
+ .endr
+#endif
+ _entry a1, 48
+#if XCHAL_NUM_AREGS % 12 == 0
+ mov a8, a8
+#elif XCHAL_NUM_AREGS % 12 == 4
+ mov a12, a12
+#elif XCHAL_NUM_AREGS % 12 == 8
+ mov a4, a4
+#endif
+ retw
+2:
+#else
+ mov a12, a12
+#endif
+ .endm
/*
* Task switch.
entry a1, 16
- mov a12, a2 # preserve 'prev' (a2)
- mov a13, a3 # and 'next' (a3)
+ mov a10, a2 # preserve 'prev' (a2)
+ mov a11, a3 # and 'next' (a3)
l32i a4, a2, TASK_THREAD_INFO
l32i a5, a3, TASK_THREAD_INFO
- save_xtregs_user a4 a6 a8 a9 a10 a11 THREAD_XTREGS_USER
+ save_xtregs_user a4 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
- s32i a0, a12, THREAD_RA # save return address
- s32i a1, a12, THREAD_SP # save stack pointer
+ s32i a0, a10, THREAD_RA # save return address
+ s32i a1, a10, THREAD_SP # save stack pointer
/* Disable ints while we manipulate the stack pointer. */
- movi a14, (1 << PS_EXCM_BIT) | LOCKLEVEL
- xsr a14, ps
+ rsil a14, LOCKLEVEL
rsr a3, excsave1
rsync
s32i a3, a3, EXC_TABLE_FIXUP /* enter critical section */
/* Flush register file. */
- call0 _spill_registers # destroys a3, a4, and SAR
+ spill_registers_kernel
/* Set kernel stack (and leave critical section)
* Note: It's save to set it here. The stack will not be overwritten
/* restore context of the task 'next' */
- l32i a0, a13, THREAD_RA # restore return address
- l32i a1, a13, THREAD_SP # restore stack pointer
+ l32i a0, a11, THREAD_RA # restore return address
+ l32i a1, a11, THREAD_SP # restore stack pointer
- load_xtregs_user a5 a6 a8 a9 a10 a11 THREAD_XTREGS_USER
+ load_xtregs_user a5 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
wsr a14, ps
- mov a2, a12 # return 'prev'
+ mov a2, a10 # return 'prev'
rsync
retw
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