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powerpc/book3e-64/kexec: create an identity TLB mapping

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book3e has no real MMU mode so we have to create an identity TLB
mapping to make sure we can access the real physical address.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
[scottwood: cleanup, and split off some changes]
Signed-off-by: Scott Wood <scottwood@freescale.com>
This commit is contained in:
Tiejun Chen 2015-10-06 22:48:18 -05:00 committed by Scott Wood
parent ecc4999f68
commit cf904e3088
1 changed files with 51 additions and 1 deletions
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52
arch/powerpc/kernel/misc_64.S
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@ -26,6 +26,7 @@
#include <asm/thread_info.h>
#include <asm/kexec.h>
#include <asm/ptrace.h>
#include <asm/mmu.h>
.text
@ -496,6 +497,51 @@ kexec_flag:
#ifdef CONFIG_KEXEC
#ifdef CONFIG_PPC_BOOK3E
/*
* BOOK3E has no real MMU mode, so we have to setup the initial TLB
* for a core to identity map v:0 to p:0. This current implementation
* assumes that 1G is enough for kexec.
*/
kexec_create_tlb:
/*
* Invalidate all non-IPROT TLB entries to avoid any TLB conflict.
* IPROT TLB entries should be >= PAGE_OFFSET and thus not conflict.
*/
PPC_TLBILX_ALL(0,R0)
sync
isync
mfspr r10,SPRN_TLB1CFG
andi. r10,r10,TLBnCFG_N_ENTRY /* Extract # entries */
subi r10,r10,1 /* Last entry: no conflict with kernel text */
lis r9,MAS0_TLBSEL(1)@h
rlwimi r9,r10,16,4,15 /* Setup MAS0 = TLBSEL | ESEL(r9) */
/* Set up a temp identity mapping v:0 to p:0 and return to it. */
#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
#define M_IF_NEEDED MAS2_M
#else
#define M_IF_NEEDED 0
#endif
mtspr SPRN_MAS0,r9
lis r9,(MAS1_VALID|MAS1_IPROT)@h
ori r9,r9,(MAS1_TSIZE(BOOK3E_PAGESZ_1GB))@l
mtspr SPRN_MAS1,r9
LOAD_REG_IMMEDIATE(r9, 0x0 | M_IF_NEEDED)
mtspr SPRN_MAS2,r9
LOAD_REG_IMMEDIATE(r9, 0x0 | MAS3_SR | MAS3_SW | MAS3_SX)
mtspr SPRN_MAS3,r9
li r9,0
mtspr SPRN_MAS7,r9
tlbwe
isync
blr
#endif
/* kexec_smp_wait(void)
*
@ -525,6 +571,10 @@ _GLOBAL(kexec_smp_wait)
* don't overwrite r3 here, it is live for kexec_wait above.
*/
real_mode: /* assume normal blr return */
#ifdef CONFIG_PPC_BOOK3E
/* Create an identity mapping. */
b kexec_create_tlb
#else
1: li r9,MSR_RI
li r10,MSR_DR|MSR_IR
mflr r11 /* return address to SRR0 */
@ -536,7 +586,7 @@ real_mode: /* assume normal blr return */
mtspr SPRN_SRR1,r10
mtspr SPRN_SRR0,r11
rfid
#endif
/*
* kexec_sequence(newstack, start, image, control, clear_all())