Initial import

1 files changed, 386 insertions, 0 deletions

diff --git a/arch/ia64/kernel/gate.S b/arch/ia64/kernel/gate.S
new file mode 100644
index 000000000..b5f8bdd86
--- /dev/null
+++ b/arch/ia64/kernel/gate.S
@@ -0,0 +1,386 @@
+/*
+ * This file contains the code that gets mapped at the upper end of each task's text
+ * region.  For now, it contains the signal trampoline code only.
+ *
+ * Copyright (C) 1999-2003 Hewlett-Packard Co
+ * 	David Mosberger-Tang <davidm@hpl.hp.com>
+ */
+
+
+#include <asm/asmmacro.h>
+#include <asm/errno.h>
+#include <asm/asm-offsets.h>
+#include <asm/sigcontext.h>
+#include <asm/unistd.h>
+#include <asm/kregs.h>
+#include <asm/page.h>
+#include "paravirt_inst.h"
+
+/*
+ * We can't easily refer to symbols inside the kernel.  To avoid full runtime relocation,
+ * complications with the linker (which likes to create PLT stubs for branches
+ * to targets outside the shared object) and to avoid multi-phase kernel builds, we
+ * simply create minimalistic "patch lists" in special ELF sections.
+ */
+	.section ".data..patch.fsyscall_table", "a"
+	.previous
+#define LOAD_FSYSCALL_TABLE(reg)			\
+[1:]	movl reg=0;					\
+	.xdata4 ".data..patch.fsyscall_table", 1b-.
+
+	.section ".data..patch.brl_fsys_bubble_down", "a"
+	.previous
+#define BRL_COND_FSYS_BUBBLE_DOWN(pr)			\
+[1:](pr)brl.cond.sptk 0;				\
+	;;						\
+	.xdata4 ".data..patch.brl_fsys_bubble_down", 1b-.
+
+GLOBAL_ENTRY(__kernel_syscall_via_break)
+	.prologue
+	.altrp b6
+	.body
+	/*
+	 * Note: for (fast) syscall restart to work, the break instruction must be
+	 *	 the first one in the bundle addressed by syscall_via_break.
+	 */
+{ .mib
+	break 0x100000
+	nop.i 0
+	br.ret.sptk.many b6
+}
+END(__kernel_syscall_via_break)
+
+#	define ARG0_OFF		(16 + IA64_SIGFRAME_ARG0_OFFSET)
+#	define ARG1_OFF		(16 + IA64_SIGFRAME_ARG1_OFFSET)
+#	define ARG2_OFF		(16 + IA64_SIGFRAME_ARG2_OFFSET)
+#	define SIGHANDLER_OFF	(16 + IA64_SIGFRAME_HANDLER_OFFSET)
+#	define SIGCONTEXT_OFF	(16 + IA64_SIGFRAME_SIGCONTEXT_OFFSET)
+
+#	define FLAGS_OFF	IA64_SIGCONTEXT_FLAGS_OFFSET
+#	define CFM_OFF		IA64_SIGCONTEXT_CFM_OFFSET
+#	define FR6_OFF		IA64_SIGCONTEXT_FR6_OFFSET
+#	define BSP_OFF		IA64_SIGCONTEXT_AR_BSP_OFFSET
+#	define RNAT_OFF		IA64_SIGCONTEXT_AR_RNAT_OFFSET
+#	define UNAT_OFF		IA64_SIGCONTEXT_AR_UNAT_OFFSET
+#	define FPSR_OFF		IA64_SIGCONTEXT_AR_FPSR_OFFSET
+#	define PR_OFF		IA64_SIGCONTEXT_PR_OFFSET
+#	define RP_OFF		IA64_SIGCONTEXT_IP_OFFSET
+#	define SP_OFF		IA64_SIGCONTEXT_R12_OFFSET
+#	define RBS_BASE_OFF	IA64_SIGCONTEXT_RBS_BASE_OFFSET
+#	define LOADRS_OFF	IA64_SIGCONTEXT_LOADRS_OFFSET
+#	define base0		r2
+#	define base1		r3
+	/*
+	 * When we get here, the memory stack looks like this:
+	 *
+	 *   +===============================+
+       	 *   |				     |
+       	 *   //	    struct sigframe          //
+       	 *   |				     |
+	 *   +-------------------------------+ <-- sp+16
+	 *   |      16 byte of scratch       |
+	 *   |            space              |
+	 *   +-------------------------------+ <-- sp
+	 *
+	 * The register stack looks _exactly_ the way it looked at the time the signal
+	 * occurred.  In other words, we're treading on a potential mine-field: each
+	 * incoming general register may be a NaT value (including sp, in which case the
+	 * process ends up dying with a SIGSEGV).
+	 *
+	 * The first thing need to do is a cover to get the registers onto the backing
+	 * store.  Once that is done, we invoke the signal handler which may modify some
+	 * of the machine state.  After returning from the signal handler, we return
+	 * control to the previous context by executing a sigreturn system call.  A signal
+	 * handler may call the rt_sigreturn() function to directly return to a given
+	 * sigcontext.  However, the user-level sigreturn() needs to do much more than
+	 * calling the rt_sigreturn() system call as it needs to unwind the stack to
+	 * restore preserved registers that may have been saved on the signal handler's
+	 * call stack.
+	 */
+
+#define SIGTRAMP_SAVES										\
+	.unwabi 3, 's';		/* mark this as a sigtramp handler (saves scratch regs) */	\
+	.unwabi @svr4, 's'; /* backwards compatibility with old unwinders (remove in v2.7) */	\
+	.savesp ar.unat, UNAT_OFF+SIGCONTEXT_OFF;						\
+	.savesp ar.fpsr, FPSR_OFF+SIGCONTEXT_OFF;						\
+	.savesp pr, PR_OFF+SIGCONTEXT_OFF;     							\
+	.savesp rp, RP_OFF+SIGCONTEXT_OFF;							\
+	.savesp ar.pfs, CFM_OFF+SIGCONTEXT_OFF;							\
+	.vframesp SP_OFF+SIGCONTEXT_OFF
+
+GLOBAL_ENTRY(__kernel_sigtramp)
+	// describe the state that is active when we get here:
+	.prologue
+	SIGTRAMP_SAVES
+	.body
+
+	.label_state 1
+
+	adds base0=SIGHANDLER_OFF,sp
+	adds base1=RBS_BASE_OFF+SIGCONTEXT_OFF,sp
+	br.call.sptk.many rp=1f
+1:
+	ld8 r17=[base0],(ARG0_OFF-SIGHANDLER_OFF)	// get pointer to signal handler's plabel
+	ld8 r15=[base1]					// get address of new RBS base (or NULL)
+	cover				// push args in interrupted frame onto backing store
+	;;
+	cmp.ne p1,p0=r15,r0		// do we need to switch rbs? (note: pr is saved by kernel)
+	mov.m r9=ar.bsp			// fetch ar.bsp
+	.spillsp.p p1, ar.rnat, RNAT_OFF+SIGCONTEXT_OFF
+(p1)	br.cond.spnt setup_rbs		// yup -> (clobbers p8, r14-r16, and r18-r20)
+back_from_setup_rbs:
+	alloc r8=ar.pfs,0,0,3,0
+	ld8 out0=[base0],16		// load arg0 (signum)
+	adds base1=(ARG1_OFF-(RBS_BASE_OFF+SIGCONTEXT_OFF)),base1
+	;;
+	ld8 out1=[base1]		// load arg1 (siginfop)
+	ld8 r10=[r17],8			// get signal handler entry point
+	;;
+	ld8 out2=[base0]		// load arg2 (sigcontextp)
+	ld8 gp=[r17]			// get signal handler's global pointer
+	adds base0=(BSP_OFF+SIGCONTEXT_OFF),sp
+	;;
+	.spillsp ar.bsp, BSP_OFF+SIGCONTEXT_OFF
+	st8 [base0]=r9			// save sc_ar_bsp
+	adds base0=(FR6_OFF+SIGCONTEXT_OFF),sp
+	adds base1=(FR6_OFF+16+SIGCONTEXT_OFF),sp
+	;;
+	stf.spill [base0]=f6,32
+	stf.spill [base1]=f7,32
+	;;
+	stf.spill [base0]=f8,32
+	stf.spill [base1]=f9,32
+	mov b6=r10
+	;;
+	stf.spill [base0]=f10,32
+	stf.spill [base1]=f11,32
+	;;
+	stf.spill [base0]=f12,32
+	stf.spill [base1]=f13,32
+	;;
+	stf.spill [base0]=f14,32
+	stf.spill [base1]=f15,32
+	br.call.sptk.many rp=b6			// call the signal handler
+.ret0:	adds base0=(BSP_OFF+SIGCONTEXT_OFF),sp
+	;;
+	ld8 r15=[base0]				// fetch sc_ar_bsp
+	mov r14=ar.bsp
+	;;
+	cmp.ne p1,p0=r14,r15			// do we need to restore the rbs?
+(p1)	br.cond.spnt restore_rbs		// yup -> (clobbers r14-r18, f6 & f7)
+	;;
+back_from_restore_rbs:
+	adds base0=(FR6_OFF+SIGCONTEXT_OFF),sp
+	adds base1=(FR6_OFF+16+SIGCONTEXT_OFF),sp
+	;;
+	ldf.fill f6=[base0],32
+	ldf.fill f7=[base1],32
+	;;
+	ldf.fill f8=[base0],32
+	ldf.fill f9=[base1],32
+	;;
+	ldf.fill f10=[base0],32
+	ldf.fill f11=[base1],32
+	;;
+	ldf.fill f12=[base0],32
+	ldf.fill f13=[base1],32
+	;;
+	ldf.fill f14=[base0],32
+	ldf.fill f15=[base1],32
+	mov r15=__NR_rt_sigreturn
+	.restore sp				// pop .prologue
+	break __BREAK_SYSCALL
+
+	.prologue
+	SIGTRAMP_SAVES
+setup_rbs:
+	mov ar.rsc=0				// put RSE into enforced lazy mode
+	;;
+	.save ar.rnat, r19
+	mov r19=ar.rnat				// save RNaT before switching backing store area
+	adds r14=(RNAT_OFF+SIGCONTEXT_OFF),sp
+
+	mov r18=ar.bspstore
+	mov ar.bspstore=r15			// switch over to new register backing store area
+	;;
+
+	.spillsp ar.rnat, RNAT_OFF+SIGCONTEXT_OFF
+	st8 [r14]=r19				// save sc_ar_rnat
+	.body
+	mov.m r16=ar.bsp			// sc_loadrs <- (new bsp - new bspstore) << 16
+	adds r14=(LOADRS_OFF+SIGCONTEXT_OFF),sp
+	;;
+	invala
+	sub r15=r16,r15
+	extr.u r20=r18,3,6
+	;;
+	mov ar.rsc=0xf				// set RSE into eager mode, pl 3
+	cmp.eq p8,p0=63,r20
+	shl r15=r15,16
+	;;
+	st8 [r14]=r15				// save sc_loadrs
+(p8)	st8 [r18]=r19		// if bspstore points at RNaT slot, store RNaT there now
+	.restore sp				// pop .prologue
+	br.cond.sptk back_from_setup_rbs
+
+	.prologue
+	SIGTRAMP_SAVES
+	.spillsp ar.rnat, RNAT_OFF+SIGCONTEXT_OFF
+	.body
+restore_rbs:
+	// On input:
+	//	r14 = bsp1 (bsp at the time of return from signal handler)
+	//	r15 = bsp0 (bsp at the time the signal occurred)
+	//
+	// Here, we need to calculate bspstore0, the value that ar.bspstore needs
+	// to be set to, based on bsp0 and the size of the dirty partition on
+	// the alternate stack (sc_loadrs >> 16).  This can be done with the
+	// following algorithm:
+	//
+	//  bspstore0 = rse_skip_regs(bsp0, -rse_num_regs(bsp1 - (loadrs >> 19), bsp1));
+	//
+	// This is what the code below does.
+	//
+	alloc r2=ar.pfs,0,0,0,0			// alloc null frame
+	adds r16=(LOADRS_OFF+SIGCONTEXT_OFF),sp
+	adds r18=(RNAT_OFF+SIGCONTEXT_OFF),sp
+	;;
+	ld8 r17=[r16]
+	ld8 r16=[r18]			// get new rnat
+	extr.u r18=r15,3,6	// r18 <- rse_slot_num(bsp0)
+	;;
+	mov ar.rsc=r17			// put RSE into enforced lazy mode
+	shr.u r17=r17,16
+	;;
+	sub r14=r14,r17		// r14 (bspstore1) <- bsp1 - (sc_loadrs >> 16)
+	shr.u r17=r17,3		// r17 <- (sc_loadrs >> 19)
+	;;
+	loadrs			// restore dirty partition
+	extr.u r14=r14,3,6	// r14 <- rse_slot_num(bspstore1)
+	;;
+	add r14=r14,r17		// r14 <- rse_slot_num(bspstore1) + (sc_loadrs >> 19)
+	;;
+	shr.u r14=r14,6		// r14 <- (rse_slot_num(bspstore1) + (sc_loadrs >> 19))/0x40
+	;;
+	sub r14=r14,r17		// r14 <- -rse_num_regs(bspstore1, bsp1)
+	movl r17=0x8208208208208209
+	;;
+	add r18=r18,r14		// r18 (delta) <- rse_slot_num(bsp0) - rse_num_regs(bspstore1,bsp1)
+	setf.sig f7=r17
+	cmp.lt p7,p0=r14,r0	// p7 <- (r14 < 0)?
+	;;
+(p7)	adds r18=-62,r18	// delta -= 62
+	;;
+	setf.sig f6=r18
+	;;
+	xmpy.h f6=f6,f7
+	;;
+	getf.sig r17=f6
+	;;
+	add r17=r17,r18
+	shr r18=r18,63
+	;;
+	shr r17=r17,5
+	;;
+	sub r17=r17,r18		// r17 = delta/63
+	;;
+	add r17=r14,r17		// r17 <- delta/63 - rse_num_regs(bspstore1, bsp1)
+	;;
+	shladd r15=r17,3,r15	// r15 <- bsp0 + 8*(delta/63 - rse_num_regs(bspstore1, bsp1))
+	;;
+	mov ar.bspstore=r15			// switch back to old register backing store area
+	;;
+	mov ar.rnat=r16				// restore RNaT
+	mov ar.rsc=0xf				// (will be restored later on from sc_ar_rsc)
+	// invala not necessary as that will happen when returning to user-mode
+	br.cond.sptk back_from_restore_rbs
+END(__kernel_sigtramp)
+
+/*
+ * On entry:
+ *	r11 = saved ar.pfs
+ *	r15 = system call #
+ *	b0  = saved return address
+ *	b6  = return address
+ * On exit:
+ *	r11 = saved ar.pfs
+ *	r15 = system call #
+ *	b0  = saved return address
+ *	all other "scratch" registers:	undefined
+ *	all "preserved" registers:	same as on entry
+ */
+
+GLOBAL_ENTRY(__kernel_syscall_via_epc)
+	.prologue
+	.altrp b6
+	.body
+{
+	/*
+	 * Note: the kernel cannot assume that the first two instructions in this
+	 * bundle get executed.  The remaining code must be safe even if
+	 * they do not get executed.
+	 */
+	adds r17=-1024,r15			// A
+	mov r10=0				// A    default to successful syscall execution
+	epc					// B	causes split-issue
+}
+	;;
+	RSM_PSR_BE_I(r20, r22)			// M2 (5 cyc to srlz.d)
+	LOAD_FSYSCALL_TABLE(r14)		// X
+	;;
+	mov r16=IA64_KR(CURRENT)		// M2 (12 cyc)
+	shladd r18=r17,3,r14			// A
+	mov r19=NR_syscalls-1			// A
+	;;
+	lfetch [r18]				// M0|1
+	MOV_FROM_PSR(p0, r29, r8)		// M2 (12 cyc)
+	// If r17 is a NaT, p6 will be zero
+	cmp.geu p6,p7=r19,r17			// A    (sysnr > 0 && sysnr < 1024+NR_syscalls)?
+	;;
+	mov r21=ar.fpsr				// M2 (12 cyc)
+	tnat.nz p10,p9=r15			// I0
+	mov.i r26=ar.pfs			// I0 (would stall anyhow due to srlz.d...)
+	;;
+	srlz.d					// M0 (forces split-issue) ensure PSR.BE==0
+(p6)	ld8 r18=[r18]				// M0|1
+	nop.i 0
+	;;
+	nop.m 0
+(p6)	tbit.z.unc p8,p0=r18,0			// I0 (dual-issues with "mov b7=r18"!)
+	nop.i 0
+	;;
+	SSM_PSR_I(p8, p14, r25)
+(p6)	mov b7=r18				// I0
+(p8)	br.dptk.many b7				// B
+
+	mov r27=ar.rsc				// M2 (12 cyc)
+/*
+ * brl.cond doesn't work as intended because the linker would convert this branch
+ * into a branch to a PLT.  Perhaps there will be a way to avoid this with some
+ * future version of the linker.  In the meantime, we just use an indirect branch
+ * instead.
+ */
+#ifdef CONFIG_ITANIUM
+(p6)	add r14=-8,r14				// r14 <- addr of fsys_bubble_down entry
+	;;
+(p6)	ld8 r14=[r14]				// r14 <- fsys_bubble_down
+	;;
+(p6)	mov b7=r14
+(p6)	br.sptk.many b7
+#else
+	BRL_COND_FSYS_BUBBLE_DOWN(p6)
+#endif
+	SSM_PSR_I(p0, p14, r10)
+	mov r10=-1
+(p10)	mov r8=EINVAL
+(p9)	mov r8=ENOSYS
+	FSYS_RETURN
+
+#ifdef CONFIG_PARAVIRT
+	/*
+	 * padd to make the size of this symbol constant
+	 * independent of paravirtualization.
+	 */
+	.align PAGE_SIZE / 8
+#endif
+END(__kernel_syscall_via_epc)