From 3ff72be4c9ce269c5b7adff9b0f912a2df3cb987 Mon Sep 17 00:00:00 2001 From: "Steven J. Hill" Date: Tue, 13 Dec 2016 14:25:37 -0600 Subject: [PATCH] MIPS: Octeon: Enable KASLR This patch enables KASLR for Octeon systems. The SMP startup code is such that the secondaries monitor the volatile variable 'octeon_processor_relocated_kernel_entry' for any non-zero value. The 'plat_post_relocation hook' is used to set that value to the kernel entry point of the relocated kernel. The secondary CPUs will then jusmp to the new kernel, perform their initialization again and begin waiting for the boot CPU to start them via the relocated loop 'octeon_spin_wait_boot'. Inspired by Steven's code from Cavium. Signed-off-by: Matt Redfearn Signed-off-by: Steven J. Hill Acked-by: David Daney Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14669/ Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 3 ++- arch/mips/cavium-octeon/smp.c | 20 +++++++++++++++++-- .../mach-cavium-octeon/kernel-entry-init.h | 15 ++++++++++++-- 3 files changed, 33 insertions(+), 5 deletions(-) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 80832aa8e4fb..7cb4b0e5f49a 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -910,6 +910,7 @@ config CAVIUM_OCTEON_SOC select NR_CPUS_DEFAULT_16 select BUILTIN_DTB select MTD_COMPLEX_MAPPINGS + select SYS_SUPPORTS_RELOCATABLE help This option supports all of the Octeon reference boards from Cavium Networks. It builds a kernel that dynamically determines the Octeon @@ -2571,7 +2572,7 @@ config SYS_SUPPORTS_NUMA config RELOCATABLE bool "Relocatable kernel" - depends on SYS_SUPPORTS_RELOCATABLE && (CPU_MIPS32_R2 || CPU_MIPS64_R2 || CPU_MIPS32_R6 || CPU_MIPS64_R6) + depends on SYS_SUPPORTS_RELOCATABLE && (CPU_MIPS32_R2 || CPU_MIPS64_R2 || CPU_MIPS32_R6 || CPU_MIPS64_R6 || CAVIUM_OCTEON_SOC) help This builds a kernel image that retains relocation information so it can be loaded someplace besides the default 1MB. diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c index 256fe6f65cf2..889c3f49dbc0 100644 --- a/arch/mips/cavium-octeon/smp.c +++ b/arch/mips/cavium-octeon/smp.c @@ -24,12 +24,17 @@ volatile unsigned long octeon_processor_boot = 0xff; volatile unsigned long octeon_processor_sp; volatile unsigned long octeon_processor_gp; +#ifdef CONFIG_RELOCATABLE +volatile unsigned long octeon_processor_relocated_kernel_entry; +#endif /* CONFIG_RELOCATABLE */ #ifdef CONFIG_HOTPLUG_CPU uint64_t octeon_bootloader_entry_addr; EXPORT_SYMBOL(octeon_bootloader_entry_addr); #endif +extern void kernel_entry(unsigned long arg1, ...); + static void octeon_icache_flush(void) { asm volatile ("synci 0($0)\n"); @@ -180,6 +185,19 @@ static void __init octeon_smp_setup(void) octeon_smp_hotplug_setup(); } + +#ifdef CONFIG_RELOCATABLE +int plat_post_relocation(long offset) +{ + unsigned long entry = (unsigned long)kernel_entry; + + /* Send secondaries into relocated kernel */ + octeon_processor_relocated_kernel_entry = entry + offset; + + return 0; +} +#endif /* CONFIG_RELOCATABLE */ + /** * Firmware CPU startup hook * @@ -333,8 +351,6 @@ void play_dead(void) ; } -extern void kernel_entry(unsigned long arg1, ...); - static void start_after_reset(void) { kernel_entry(0, 0, 0); /* set a2 = 0 for secondary core */ diff --git a/arch/mips/include/asm/mach-cavium-octeon/kernel-entry-init.h b/arch/mips/include/asm/mach-cavium-octeon/kernel-entry-init.h index c4873e8594ef..c38b38ce5a3d 100644 --- a/arch/mips/include/asm/mach-cavium-octeon/kernel-entry-init.h +++ b/arch/mips/include/asm/mach-cavium-octeon/kernel-entry-init.h @@ -99,9 +99,20 @@ # to begin # - # This is the variable where the next core to boot os stored - PTR_LA t0, octeon_processor_boot octeon_spin_wait_boot: +#ifdef CONFIG_RELOCATABLE + PTR_LA t0, octeon_processor_relocated_kernel_entry + LONG_L t0, (t0) + beq zero, t0, 1f + nop + + jr t0 + nop +1: +#endif /* CONFIG_RELOCATABLE */ + + # This is the variable where the next core to boot is stored + PTR_LA t0, octeon_processor_boot # Get the core id of the next to be booted LONG_L t1, (t0) # Keep looping if it isn't me