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linux-pinenote/arch/parisc/kernel/head.S
Helge Deller 161bd3bf60 parisc: fix kernel memory layout in vmlinux.ld.S 
When building a 64bit kernel sometimes functions in the .init section were not
able to reach the standard kernel function. Main reason for this problem is,
that the linkage tables (.plt, .opd, .dlt) tend to become pretty huge and thus
the distance gets too big for short calls.

One option to avoid this is to use the -mlong-calls compiler option, but this
increases the binary size and introduces a performance penalty.

Instead, with this patch we just lay out the binary differently.  Init code is
stored first, followed by text, R/O and finally R/W data. This means, that init
and text code is now much closer to each other, which is sufficient to reach
each other by short calls.

Signed-off-by: Helge Deller <deller@gmx.de>
2013-11-30 22:09:21 +01:00

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/* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1999-2007 by Helge Deller <deller@gmx.de>
* Copyright 1999 SuSE GmbH (Philipp Rumpf)
* Copyright 1999 Philipp Rumpf (prumpf@tux.org)
* Copyright 2000 Hewlett Packard (Paul Bame, bame@puffin.external.hp.com)
* Copyright (C) 2001 Grant Grundler (Hewlett Packard)
* Copyright (C) 2004 Kyle McMartin <kyle@debian.org>
*
* Initial Version 04-23-1999 by Helge Deller <deller@gmx.de>
*/
#include <asm/asm-offsets.h>
#include <asm/psw.h>
#include <asm/pdc.h>
#include <asm/assembly.h>
#include <asm/pgtable.h>
#include <linux/linkage.h>
#include <linux/init.h>
.level LEVEL
__INITDATA
ENTRY(boot_args)
.word 0 /* arg0 */
.word 0 /* arg1 */
.word 0 /* arg2 */
.word 0 /* arg3 */
END(boot_args)
__HEAD
.align 4
.import init_thread_union,data
.import fault_vector_20,code /* IVA parisc 2.0 32 bit */
#ifndef CONFIG_64BIT
.import fault_vector_11,code /* IVA parisc 1.1 32 bit */
.import $global$ /* forward declaration */
#endif /*!CONFIG_64BIT*/
ENTRY(parisc_kernel_start)
.proc
.callinfo
/* Make sure sr4-sr7 are set to zero for the kernel address space */
mtsp %r0,%sr4
mtsp %r0,%sr5
mtsp %r0,%sr6
mtsp %r0,%sr7
/* Clear BSS (shouldn't the boot loader do this?) */
.import __bss_start,data
.import __bss_stop,data
load32 PA(__bss_start),%r3
load32 PA(__bss_stop),%r4
$bss_loop:
cmpb,<<,n %r3,%r4,$bss_loop
stw,ma %r0,4(%r3)
/* Save away the arguments the boot loader passed in (32 bit args) */
load32 PA(boot_args),%r1
stw,ma %arg0,4(%r1)
stw,ma %arg1,4(%r1)
stw,ma %arg2,4(%r1)
stw,ma %arg3,4(%r1)
/* Initialize startup VM. Just map first 8/16 MB of memory */
load32 PA(swapper_pg_dir),%r4
mtctl %r4,%cr24 /* Initialize kernel root pointer */
mtctl %r4,%cr25 /* Initialize user root pointer */
#if PT_NLEVELS == 3
/* Set pmd in pgd */
load32 PA(pmd0),%r5
shrd %r5,PxD_VALUE_SHIFT,%r3
ldo (PxD_FLAG_PRESENT+PxD_FLAG_VALID)(%r3),%r3
stw %r3,ASM_PGD_ENTRY*ASM_PGD_ENTRY_SIZE(%r4)
ldo ASM_PMD_ENTRY*ASM_PMD_ENTRY_SIZE(%r5),%r4
#else
/* 2-level page table, so pmd == pgd */
ldo ASM_PGD_ENTRY*ASM_PGD_ENTRY_SIZE(%r4),%r4
#endif
/* Fill in pmd with enough pte directories */
load32 PA(pg0),%r1
SHRREG %r1,PxD_VALUE_SHIFT,%r3
ldo (PxD_FLAG_PRESENT+PxD_FLAG_VALID)(%r3),%r3
ldi ASM_PT_INITIAL,%r1
1:
stw %r3,0(%r4)
ldo (PAGE_SIZE >> PxD_VALUE_SHIFT)(%r3),%r3
addib,> -1,%r1,1b
#if PT_NLEVELS == 3
ldo ASM_PMD_ENTRY_SIZE(%r4),%r4
#else
ldo ASM_PGD_ENTRY_SIZE(%r4),%r4
#endif
/* Now initialize the PTEs themselves. We use RWX for
* everything ... it will get remapped correctly later */
ldo 0+_PAGE_KERNEL_RWX(%r0),%r3 /* Hardwired 0 phys addr start */
ldi (1<<(KERNEL_INITIAL_ORDER-PAGE_SHIFT)),%r11 /* PFN count */
load32 PA(pg0),%r1
$pgt_fill_loop:
STREGM %r3,ASM_PTE_ENTRY_SIZE(%r1)
ldo (1<<PFN_PTE_SHIFT)(%r3),%r3 /* add one PFN */
addib,> -1,%r11,$pgt_fill_loop
nop
/* Load the return address...er...crash 'n burn */
copy %r0,%r2
/* And the RFI Target address too */
load32 start_parisc,%r11
/* And the initial task pointer */
load32 init_thread_union,%r6
mtctl %r6,%cr30
/* And the stack pointer too */
ldo THREAD_SZ_ALGN(%r6),%sp
#ifdef CONFIG_SMP
/* Set the smp rendezvous address into page zero.
** It would be safer to do this in init_smp_config() but
** it's just way easier to deal with here because
** of 64-bit function ptrs and the address is local to this file.
*/
load32 PA(smp_slave_stext),%r10
stw %r10,0x10(%r0) /* MEM_RENDEZ */
stw %r0,0x28(%r0) /* MEM_RENDEZ_HI - assume addr < 4GB */
/* FALLTHROUGH */
.procend
/*
** Code Common to both Monarch and Slave processors.
** Entry:
**
** 1.1:
** %r11 must contain RFI target address.
** %r25/%r26 args to pass to target function
** %r2 in case rfi target decides it didn't like something
**
** 2.0w:
** %r3 PDCE_PROC address
** %r11 RFI target address
**
** Caller must init: SR4-7, %sp, %r10, %cr24/25,
*/
common_stext:
.proc
.callinfo
#else
/* Clear PDC entry point - we won't use it */
stw %r0,0x10(%r0) /* MEM_RENDEZ */
stw %r0,0x28(%r0) /* MEM_RENDEZ_HI */
#endif /*CONFIG_SMP*/
#ifdef CONFIG_64BIT
tophys_r1 %sp
/* Save the rfi target address */
ldd TI_TASK-THREAD_SZ_ALGN(%sp), %r10
tophys_r1 %r10
std %r11, TASK_PT_GR11(%r10)
/* Switch to wide mode Superdome doesn't support narrow PDC
** calls.
*/
1: mfia %rp /* clear upper part of pcoq */
ldo 2f-1b(%rp),%rp
depdi 0,31,32,%rp
bv (%rp)
ssm PSW_SM_W,%r0
/* Set Wide mode as the "Default" (eg for traps)
** First trap occurs *right* after (or part of) rfi for slave CPUs.
** Someday, palo might not do this for the Monarch either.
*/
2:
#define MEM_PDC_LO 0x388
#define MEM_PDC_HI 0x35C
ldw MEM_PDC_LO(%r0),%r3
ldw MEM_PDC_HI(%r0),%r6
depd %r6, 31, 32, %r3 /* move to upper word */
mfctl %cr30,%r6 /* PCX-W2 firmware bug */
ldo PDC_PSW(%r0),%arg0 /* 21 */
ldo PDC_PSW_SET_DEFAULTS(%r0),%arg1 /* 2 */
ldo PDC_PSW_WIDE_BIT(%r0),%arg2 /* 2 */
load32 PA(stext_pdc_ret), %rp
bv (%r3)
copy %r0,%arg3
stext_pdc_ret:
mtctl %r6,%cr30 /* restore task thread info */
/* restore rfi target address*/
ldd TI_TASK-THREAD_SZ_ALGN(%sp), %r10
tophys_r1 %r10
ldd TASK_PT_GR11(%r10), %r11
tovirt_r1 %sp
#endif
/* PARANOID: clear user scratch/user space SR's */
mtsp %r0,%sr0
mtsp %r0,%sr1
mtsp %r0,%sr2
mtsp %r0,%sr3
/* Initialize Protection Registers */
mtctl %r0,%cr8
mtctl %r0,%cr9
mtctl %r0,%cr12
mtctl %r0,%cr13
/* Initialize the global data pointer */
loadgp
/* Set up our interrupt table. HPMCs might not work after this!
*
* We need to install the correct iva for PA1.1 or PA2.0. The
* following short sequence of instructions can determine this
* (without being illegal on a PA1.1 machine).
*/
#ifndef CONFIG_64BIT
ldi 32,%r10
mtctl %r10,%cr11
.level 2.0
mfctl,w %cr11,%r10
.level 1.1
comib,<>,n 0,%r10,$is_pa20
ldil L%PA(fault_vector_11),%r10
b $install_iva
ldo R%PA(fault_vector_11)(%r10),%r10
$is_pa20:
.level LEVEL /* restore 1.1 || 2.0w */
#endif /*!CONFIG_64BIT*/
load32 PA(fault_vector_20),%r10
$install_iva:
mtctl %r10,%cr14
b aligned_rfi /* Prepare to RFI! Man all the cannons! */
nop
.align 128
aligned_rfi:
pcxt_ssm_bug
rsm PSW_SM_QUIET,%r0 /* off troublesome PSW bits */
/* Don't need NOPs, have 8 compliant insn before rfi */
mtctl %r0,%cr17 /* Clear IIASQ tail */
mtctl %r0,%cr17 /* Clear IIASQ head */
/* Load RFI target into PC queue */
mtctl %r11,%cr18 /* IIAOQ head */
ldo 4(%r11),%r11
mtctl %r11,%cr18 /* IIAOQ tail */
load32 KERNEL_PSW,%r10
mtctl %r10,%ipsw
/* Jump through hyperspace to Virt Mode */
rfi
nop
.procend
#ifdef CONFIG_SMP
.import smp_init_current_idle_task,data
.import smp_callin,code
#ifndef CONFIG_64BIT
smp_callin_rtn:
.proc
.callinfo
break 1,1 /* Break if returned from start_secondary */
nop
nop
.procend
#endif /*!CONFIG_64BIT*/
/***************************************************************************
* smp_slave_stext is executed by all non-monarch Processors when the Monarch
* pokes the slave CPUs in smp.c:smp_boot_cpus().
*
* Once here, registers values are initialized in order to branch to virtual
* mode. Once all available/eligible CPUs are in virtual mode, all are
* released and start out by executing their own idle task.
*****************************************************************************/
smp_slave_stext:
.proc
.callinfo
/*
** Initialize Space registers
*/
mtsp %r0,%sr4
mtsp %r0,%sr5
mtsp %r0,%sr6
mtsp %r0,%sr7
/* Initialize the SP - monarch sets up smp_init_current_idle_task */
load32 PA(smp_init_current_idle_task),%sp
LDREG 0(%sp),%sp /* load task address */
tophys_r1 %sp
LDREG TASK_THREAD_INFO(%sp),%sp
mtctl %sp,%cr30 /* store in cr30 */
ldo THREAD_SZ_ALGN(%sp),%sp
/* point CPU to kernel page tables */
load32 PA(swapper_pg_dir),%r4
mtctl %r4,%cr24 /* Initialize kernel root pointer */
mtctl %r4,%cr25 /* Initialize user root pointer */
#ifdef CONFIG_64BIT
/* Setup PDCE_PROC entry */
copy %arg0,%r3
#else
/* Load RFI *return* address in case smp_callin bails */
load32 smp_callin_rtn,%r2
#endif
/* Load RFI target address. */
load32 smp_callin,%r11
/* ok...common code can handle the rest */
b common_stext
nop
.procend
#endif /* CONFIG_SMP */
ENDPROC(parisc_kernel_start)
#ifndef CONFIG_64BIT
.section .data..read_mostly
.align 4
.export $global$,data
.type $global$,@object
.size $global$,4
$global$:
.word 0
#endif /*!CONFIG_64BIT*/
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