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authorMark Rutland <mark.rutland@arm.com>2013-10-24 20:30:16 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2013-10-25 11:33:20 +0100
commit652af899799354049b273af897b798b8f03fdd88 (patch)
treeb251c256f8589168401dd0cc794f2574f48fcf44 /arch/arm64/kernel/head.S
parentcd1aebf5277a3a154a9e4c0ea4b3acabb62e5cab (diff)
downloadlinux-linaro-stable-652af899799354049b273af897b798b8f03fdd88.tar.gz
arm64: factor out spin-table boot method
The arm64 kernel has an internal holding pen, which is necessary for some systems where we can't bring CPUs online individually and must hold multiple CPUs in a safe area until the kernel is able to handle them. The current SMP infrastructure for arm64 is closely coupled to this holding pen, and alternative boot methods must launch CPUs into the pen, where they sit before they are launched into the kernel proper. With PSCI (and possibly other future boot methods), we can bring CPUs online individually, and need not perform the secondary_holding_pen dance. Instead, this patch factors the holding pen management code out to the spin-table boot method code, as it is the only boot method requiring the pen. A new entry point for secondaries, secondary_entry is added for other boot methods to use, which bypasses the holding pen and its associated overhead when bringing CPUs online. The smp.pen.text section is also removed, as the pen can live in head.text without problem. The cpu_operations structure is extended with two new functions, cpu_boot and cpu_postboot, for bringing a cpu into the kernel and performing any post-boot cleanup required by a bootmethod (e.g. resetting the secondary_holding_pen_release to INVALID_HWID). Documentation is added for cpu_operations. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/head.S')
-rw-r--r--arch/arm64/kernel/head.S12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 7090c126797c..bf7efdf2d7e7 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -225,7 +225,6 @@ ENTRY(__boot_cpu_mode)
.quad PAGE_OFFSET
#ifdef CONFIG_SMP
- .pushsection .smp.pen.text, "ax"
.align 3
1: .quad .
.quad secondary_holding_pen_release
@@ -250,7 +249,16 @@ pen: ldr x4, [x3]
wfe
b pen
ENDPROC(secondary_holding_pen)
- .popsection
+
+ /*
+ * Secondary entry point that jumps straight into the kernel. Only to
+ * be used where CPUs are brought online dynamically by the kernel.
+ */
+ENTRY(secondary_entry)
+ bl __calc_phys_offset // x2=phys offset
+ bl el2_setup // Drop to EL1
+ b secondary_startup
+ENDPROC(secondary_entry)
ENTRY(secondary_startup)
/*