[linux-yocto] [PATCH 45/70] powerpc/47x: Kernel support for KEXEC
Paul Butler
butler.paul at gmail.com
Mon Jun 10 18:46:08 PDT 2013
From: Jiang Lu <lu.jiang at windriver.com>
commit 68343020031585f861d93e2f25589598feadaff3 upstream
This patch adds support for creating 1:1 mapping for the PPC_47x during
a KEXEC. The implementation is similar to that of the PPC440x which is
described here :
http://patchwork.ozlabs.org/patch/104323/
PPC_47x MMU :
The 47x uses Unified TLB 1024 entries, with 4-way associative mapping
(4 x 256 entries). The index to be used is calculated by the MMU by
hashing the PID, EPN and TS. The software can choose to specify the way
by setting bit 0(enable way select) and the way in bits 1-2 in the TLB
Word 0.
Implementation:
The patch erases all the UTLB entries which includes the tlb covering
the mapping for our code. The shadow TLB caches the mapping for the
running code which helps us to continue the execution until we do
isync/rfi. We then create a tmp mapping for the current code in the
other address space (TS) and switch to it.
Then we create a 1:1 mapping(EPN=RPN) for 0-2GiB in the original
address space and switch to the new mapping.
TODO: Add SMP support.
Signed-off-by: Suzuki K. Poulose <suzuki at in.ibm.com>
Signed-off-by: Josh Boyer <jwboyer at gmail.com>
Integrated-by: Wei Yang <Wei.Yang at windriver.com>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/kernel/misc_32.S | 194 ++++++++++++++++++++++++++++++++++++++++--
2 files changed, 189 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 619756f..8a850e4 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -356,7 +356,7 @@ config ARCH_ENABLE_MEMORY_HOTREMOVE
config KEXEC
bool "kexec system call (EXPERIMENTAL)"
- depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP && !PPC_47x)) && EXPERIMENTAL
+ depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP)) && EXPERIMENTAL
help
kexec is a system call that implements the ability to shutdown your
current kernel, and to start another kernel. It is like a reboot
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index e98d6b0..c85fe05 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -738,7 +738,21 @@ relocate_new_kernel:
mr r5, r31
li r0, 0
-#elif defined(CONFIG_44x) && !defined(CONFIG_PPC_47x)
+#elif defined(CONFIG_44x)
+
+ /* Save our parameters */
+ mr r29, r3
+ mr r30, r4
+ mr r31, r5
+#ifdef CONFIG_PPC_47x
+ /* Check for 47x cores */
+ mfspr r3,SPRN_PVR
+ srwi r3,r3,16
+ cmplwi cr0,r3,PVR_476 at h
+ beq setup_map_47x
+ cmplwi cr0,r3,PVR_476_ISS at h
+ beq setup_map_47x
+#endif /* CONFIG_PPC_47x */
/*
* Code for setting up 1:1 mapping for PPC440x for KEXEC
@@ -753,13 +767,8 @@ relocate_new_kernel:
* 5) Invalidate the tmp mapping.
*
* - Based on the kexec support code for FSL BookE
- * - Doesn't support 47x yet.
*
*/
- /* Save our parameters */
- mr r29, r3
- mr r30, r4
- mr r31, r5
/* Load our MSR_IS and TID to MMUCR for TLB search */
mfspr r3,SPRN_PID
@@ -900,6 +909,179 @@ next_tlb:
li r3, 0
tlbwe r3, r24, PPC44x_TLB_PAGEID
sync
+ b ppc44x_map_done
+
+#ifdef CONFIG_PPC_47x
+
+ /* 1:1 mapping for 47x */
+
+setup_map_47x:
+
+ /*
+ * Load the kernel pid (0) to PID and also to MMUCR[TID].
+ * Also set the MSR IS->MMUCR STS
+ */
+ li r3, 0
+ mtspr SPRN_PID, r3 /* Set PID */
+ mfmsr r4 /* Get MSR */
+ andi. r4, r4, MSR_IS at l /* TS=1? */
+ beq 1f /* If not, leave STS=0 */
+ oris r3, r3, PPC47x_MMUCR_STS at h /* Set STS=1 */
+1: mtspr SPRN_MMUCR, r3 /* Put MMUCR */
+ sync
+
+ /* Find the entry we are running from */
+ bl 2f
+2: mflr r23
+ tlbsx r23, 0, r23
+ tlbre r24, r23, 0 /* TLB Word 0 */
+ tlbre r25, r23, 1 /* TLB Word 1 */
+ tlbre r26, r23, 2 /* TLB Word 2 */
+
+
+ /*
+ * Invalidates all the tlb entries by writing to 256 RPNs(r4)
+ * of 4k page size in all 4 ways (0-3 in r3).
+ * This would invalidate the entire UTLB including the one we are
+ * running from. However the shadow TLB entries would help us
+ * to continue the execution, until we flush them (rfi/isync).
+ */
+ addis r3, 0, 0x8000 /* specify the way */
+ addi r4, 0, 0 /* TLB Word0 = (EPN=0, VALID = 0) */
+ addi r5, 0, 0
+ b clear_utlb_entry
+
+ /* Align the loop to speed things up. from head_44x.S */
+ .align 6
+
+clear_utlb_entry:
+
+ tlbwe r4, r3, 0
+ tlbwe r5, r3, 1
+ tlbwe r5, r3, 2
+ addis r3, r3, 0x2000 /* Increment the way */
+ cmpwi r3, 0
+ bne clear_utlb_entry
+ addis r3, 0, 0x8000
+ addis r4, r4, 0x100 /* Increment the EPN */
+ cmpwi r4, 0
+ bne clear_utlb_entry
+
+ /* Create the entries in the other address space */
+ mfmsr r5
+ rlwinm r7, r5, 27, 31, 31 /* Get the TS (Bit 26) from MSR */
+ xori r7, r7, 1 /* r7 = !TS */
+
+ insrwi r24, r7, 1, 21 /* Change the TS in the saved TLB word 0 */
+
+ /*
+ * write out the TLB entries for the tmp mapping
+ * Use way '0' so that we could easily invalidate it later.
+ */
+ lis r3, 0x8000 /* Way '0' */
+
+ tlbwe r24, r3, 0
+ tlbwe r25, r3, 1
+ tlbwe r26, r3, 2
+
+ /* Update the msr to the new TS */
+ insrwi r5, r7, 1, 26
+
+ bl 1f
+1: mflr r6
+ addi r6, r6, (2f-1b)
+
+ mtspr SPRN_SRR0, r6
+ mtspr SPRN_SRR1, r5
+ rfi
+
+ /*
+ * Now we are in the tmp address space.
+ * Create a 1:1 mapping for 0-2GiB in the original TS.
+ */
+2:
+ li r3, 0
+ li r4, 0 /* TLB Word 0 */
+ li r5, 0 /* TLB Word 1 */
+ li r6, 0
+ ori r6, r6, PPC47x_TLB2_S_RWX /* TLB word 2 */
+
+ li r8, 0 /* PageIndex */
+
+ xori r7, r7, 1 /* revert back to original TS */
+
+write_utlb:
+ rotlwi r5, r8, 28 /* RPN = PageIndex * 256M */
+ /* ERPN = 0 as we don't use memory above 2G */
+
+ mr r4, r5 /* EPN = RPN */
+ ori r4, r4, (PPC47x_TLB0_VALID | PPC47x_TLB0_256M)
+ insrwi r4, r7, 1, 21 /* Insert the TS to Word 0 */
+
+ tlbwe r4, r3, 0 /* Write out the entries */
+ tlbwe r5, r3, 1
+ tlbwe r6, r3, 2
+ addi r8, r8, 1
+ cmpwi r8, 8 /* Have we completed ? */
+ bne write_utlb
+
+ /* make sure we complete the TLB write up */
+ isync
+
+ /*
+ * Prepare to jump to the 1:1 mapping.
+ * 1) Extract page size of the tmp mapping
+ * DSIZ = TLB_Word0[22:27]
+ * 2) Calculate the physical address of the address
+ * to jump to.
+ */
+ rlwinm r10, r24, 0, 22, 27
+
+ cmpwi r10, PPC47x_TLB0_4K
+ bne 0f
+ li r10, 0x1000 /* r10 = 4k */
+ bl 1f
+
+0:
+ /* Defaults to 256M */
+ lis r10, 0x1000
+
+ bl 1f
+1: mflr r4
+ addi r4, r4, (2f-1b) /* virtual address of 2f */
+
+ subi r11, r10, 1 /* offsetmask = Pagesize - 1 */
+ not r10, r11 /* Pagemask = ~(offsetmask) */
+
+ and r5, r25, r10 /* Physical page */
+ and r6, r4, r11 /* offset within the current page */
+
+ or r5, r5, r6 /* Physical address for 2f */
+
+ /* Switch the TS in MSR to the original one */
+ mfmsr r8
+ insrwi r8, r7, 1, 26
+
+ mtspr SPRN_SRR1, r8
+ mtspr SPRN_SRR0, r5
+ rfi
+
+2:
+ /* Invalidate the tmp mapping */
+ lis r3, 0x8000 /* Way '0' */
+
+ clrrwi r24, r24, 12 /* Clear the valid bit */
+ tlbwe r24, r3, 0
+ tlbwe r25, r3, 1
+ tlbwe r26, r3, 2
+
+ /* Make sure we complete the TLB write and flush the shadow TLB */
+ isync
+
+#endif
+
+ppc44x_map_done:
+
/* Restore the parameters */
mr r3, r29
--
1.8.3
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