From 8d17004ebcd2cdcb8192500173fca67004e7c9ca Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Thu, 31 Aug 2023 13:17:46 +0200 Subject: ARM: shmobile: r8a7779: Reserve boot area when SMP is enabled CPU core bringup on R-Car H1 uses the ARM Reset Vector Address Register (AVECR) to specify the base address and size of the boot area of the System CPU. With this enabled, when the System CPU accesses a physical address in the range from zero up to the configured size, the top address bits are replaced by those specified in the AVECR register. Hence any device residing in this low part of physical address space cannot be accessed, Prevent conflicts by reserving this memory region using request_mem_region(). Signed-off-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/924961188abdf2adb52167edb7ed848a6efcca39.1693409184.git.geert+renesas@glider.be --- arch/arm/mach-shmobile/smp-r8a7779.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'arch/arm/mach-shmobile') diff --git a/arch/arm/mach-shmobile/smp-r8a7779.c b/arch/arm/mach-shmobile/smp-r8a7779.c index 1bc609986c16..474c325323a3 100644 --- a/arch/arm/mach-shmobile/smp-r8a7779.c +++ b/arch/arm/mach-shmobile/smp-r8a7779.c @@ -38,7 +38,14 @@ static int r8a7779_boot_secondary(unsigned int cpu, struct task_struct *idle) static void __init r8a7779_smp_prepare_cpus(unsigned int max_cpus) { - void __iomem *base = ioremap(HPBREG_BASE, 0x1000); + void __iomem *base; + + if (!request_mem_region(0, SZ_4K, "Boot Area")) { + pr_err("Failed to request boot area\n"); + return; + } + + base = ioremap(HPBREG_BASE, 0x1000); /* Map the reset vector (in headsmp-scu.S, headsmp.S) */ writel(__pa(shmobile_boot_vector), base + AVECR); -- cgit v1.2.3