linux-kernel - [PATCH 2/2] arm: smp: Fix SMP for xip kernels

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Message-Id: <20240731113905.3326586-2-mail2hgg@gmail.com>
Date: Wed, 31 Jul 2024 17:09:05 +0530
From: Harith George <mail2hgg@...il.com>
To: linus.walleij@...aro.org,
	linux@...linux.org.uk,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Cc: harith.g@...fsemi.com,
	akpm@...ux-foundation.org,
	rppt@...nel.org,
	rmk+kernel@...linux.org.uk,
	m.szyprowski@...sung.com,
	vishal.moola@...il.com,
	david@...hat.com,
	willy@...radead.org,
	nico@...xnic.net,
	ardb@...nel.org
Subject: [PATCH 2/2] arm: smp: Fix SMP for xip kernels

From: Harith George <harith.g@...fsemi.com>

Fix the physical address calculation of the following to get smp working
on xip kernels.
- secondary_data needed for secondary cpu bootup.
- secondary_startup address passed through psci.
- identity mapped code region needed for enabling mmu for secondary cpus.

Signed-off-by: Harith George <harith.g@...fsemi.com>
---
 arch/arm/kernel/head.S     | 4 ++++
 arch/arm/kernel/psci_smp.c | 7 +++++++
 arch/arm/mm/idmap.c        | 7 +++++++
 3 files changed, 18 insertions(+)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 28873cda464f..f22c50d4bd41 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -411,7 +411,11 @@ ENTRY(secondary_startup)
 	/*
 	 * Use the page tables supplied from  __cpu_up.
 	 */
+#ifdef CONFIG_XIP_KERNEL
+	ldr	r3, =(secondary_data + PLAT_PHYS_OFFSET - PAGE_OFFSET)
+#else
 	adr_l	r3, secondary_data
+#endif
 	mov_l	r12, __secondary_switched
 	ldrd	r4, r5, [r3, #0]		@ get secondary_data.pgdir
 ARM_BE8(eor	r4, r4, r5)			@ Swap r5 and r4 in BE:
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c
index d4392e177484..3bb0c4dcfc5c 100644
--- a/arch/arm/kernel/psci_smp.c
+++ b/arch/arm/kernel/psci_smp.c
@@ -45,8 +45,15 @@ extern void secondary_startup(void);
 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	if (psci_ops.cpu_on)
+#ifdef CONFIG_XIP_KERNEL
+		return psci_ops.cpu_on(cpu_logical_map(cpu),
+			((phys_addr_t)(&secondary_startup)
+			- XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+			+ CONFIG_XIP_PHYS_ADDR));
+#else
 		return psci_ops.cpu_on(cpu_logical_map(cpu),
 					virt_to_idmap(&secondary_startup));
+#endif
 	return -ENODEV;
 }
 
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index 448e57c6f653..4a833e89782a 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -84,8 +84,15 @@ static void identity_mapping_add(pgd_t *pgd, const char *text_start,
 	unsigned long addr, end;
 	unsigned long next;
 
+#ifdef CONFIG_XIP_KERNEL
+	addr = (phys_addr_t)(text_start) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+		+ CONFIG_XIP_PHYS_ADDR;
+	end = (phys_addr_t)(text_end) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+		+ CONFIG_XIP_PHYS_ADDR;
+#else
 	addr = virt_to_idmap(text_start);
 	end = virt_to_idmap(text_end);
+#endif
 	pr_info("Setting up static identity map for 0x%lx - 0x%lx\n", addr, end);
 
 	prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
-- 
2.34.1