linux-kernel - [PATCH v1 07/13] powerpc/mm/32s: add setibat() clearibat() and update

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Message-Id: <43cde6255c890f944700accf8769e73786794342.1543517818.git.christophe.leroy@c-s.fr>
Date:   Thu, 29 Nov 2018 19:00:24 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, j.neuschaefer@....net
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 07/13] powerpc/mm/32s: add setibat() clearibat() and
 update_bats()

setibat() and clearibat() allows to manipulate IBATs independently
of DBATs.

update_bats() allows to update bats after init. This is done
with MMU off.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/include/asm/book3s/32/mmu-hash.h |  2 ++
 arch/powerpc/kernel/head_32.S                 | 35 +++++++++++++++++++++++++++
 arch/powerpc/mm/ppc_mmu_32.c                  | 32 ++++++++++++++++++++++++
 3 files changed, 69 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/32/mmu-hash.h b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
index e38c91388c40..b4ccb832d4fb 100644
--- a/arch/powerpc/include/asm/book3s/32/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/32/mmu-hash.h
@@ -83,6 +83,8 @@ typedef struct {
 	unsigned long vdso_base;
 } mm_context_t;
 
+void update_bats(void);
+
 #endif /* !__ASSEMBLY__ */
 
 /* We happily ignore the smaller BATs on 601, we don't actually use
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index d1c39b5ccfd6..0f4c72ebb151 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -1101,6 +1101,41 @@ BEGIN_MMU_FTR_SECTION
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_HIGH_BATS)
 	blr
 
+_ENTRY(update_bats)
+	lis	r4, 1f@h
+	ori	r4, r4, 1f@l
+	tophys(r4, r4)
+	mfmsr	r6
+	mflr	r7
+	li	r3, MSR_KERNEL & ~(MSR_IR | MSR_DR)
+	rlwinm	r0, r6, 0, ~MSR_RI
+	rlwinm	r0, r0, 0, ~MSR_EE
+	mtmsr	r0
+	mtspr	SPRN_SRR0, r4
+	mtspr	SPRN_SRR1, r3
+	SYNC
+	RFI
+1:	bl	clear_bats
+	lis	r3, BATS@ha
+	addi	r3, r3, BATS@l
+	tophys(r3, r3)
+	LOAD_BAT(0, r3, r4, r5)
+	LOAD_BAT(1, r3, r4, r5)
+	LOAD_BAT(2, r3, r4, r5)
+	LOAD_BAT(3, r3, r4, r5)
+BEGIN_MMU_FTR_SECTION
+	LOAD_BAT(4, r3, r4, r5)
+	LOAD_BAT(5, r3, r4, r5)
+	LOAD_BAT(6, r3, r4, r5)
+	LOAD_BAT(7, r3, r4, r5)
+END_MMU_FTR_SECTION_IFSET(MMU_FTR_USE_HIGH_BATS)
+	li	r3, MSR_KERNEL & ~(MSR_IR | MSR_DR | MSR_RI)
+	mtmsr	r3
+	mtspr	SPRN_SRR0, r7
+	mtspr	SPRN_SRR1, r6
+	SYNC
+	RFI
+
 flush_tlbs:
 	lis	r10, 0x40
 1:	addic.	r10, r10, -0x1000
diff --git a/arch/powerpc/mm/ppc_mmu_32.c b/arch/powerpc/mm/ppc_mmu_32.c
index 1078095d9407..58dd71686707 100644
--- a/arch/powerpc/mm/ppc_mmu_32.c
+++ b/arch/powerpc/mm/ppc_mmu_32.c
@@ -105,6 +105,38 @@ static unsigned int block_size(unsigned long base, unsigned long top)
 	return min3(max_size, 1U << base_shift, 1U << block_shift);
 }
 
+/*
+ * Set up one of the IBAT (block address translation) register pairs.
+ * The parameters are not checked; in particular size must be a power
+ * of 2 between 128k and 256M.
+ * Only for 603+ ...
+ */
+static void setibat(int index, unsigned long virt, phys_addr_t phys,
+		    unsigned int size, pgprot_t prot)
+{
+	unsigned int bl = (size >> 17) - 1;
+	int wimgxpp;
+	struct ppc_bat *bat = BATS[index];
+	unsigned long flags = pgprot_val(prot);
+
+	if (!cpu_has_feature(CPU_FTR_NEED_COHERENT))
+		flags &= ~_PAGE_COHERENT;
+
+	wimgxpp = (flags & _PAGE_COHERENT) | (_PAGE_EXEC ? BPP_RX : BPP_XX);
+	bat[0].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */
+	bat[0].batl = BAT_PHYS_ADDR(phys) | wimgxpp;
+	if (flags & _PAGE_USER)
+		bat[0].batu |= 1;	/* Vp = 1 */
+}
+
+static void clearibat(int index)
+{
+	struct ppc_bat *bat = BATS[index];
+
+	bat[0].batu = 0;
+	bat[0].batl = 0;
+}
+
 unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
 {
 	int idx;
-- 
2.13.3