103 lines
2.8 KiB
Diff
103 lines
2.8 KiB
Diff
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From 5995f83592aea874f5b423538e36675e2204582b Mon Sep 17 00:00:00 2001
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From: Jaxson Han <jaxson.han@arm.com>
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Date: Tue, 4 Jan 2022 17:01:55 +0800
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Subject: [PATCH] boot: Add the --enable-keep-el compile option
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Add --enable-keep-el compile option to enable boot-wrapper booting next
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stage at EL2.
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The Armv8R AArch64 boots at EL2. If the next stage requires EL2 booting,
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the boot-wrapper should not drop to EL1.
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Currently, this option only works for Armv8R AArch64. Also, to work with
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Linux PSCI, this option will cause secondary cores booting at EL1.
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Issue-Id: SCM-3813
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Upstream-Status: Inappropriate [other]
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Implementation pending further discussion
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Signed-off-by: Jaxson Han <jaxson.han@arm.com>
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Change-Id: I3ba9c87cf0b59d163ca433f74c9e3a46e5ca2c63
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---
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Makefile.am | 4 ++++
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arch/aarch64/boot.S | 6 +++++-
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common/psci.c | 6 ++++++
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configure.ac | 5 +++++
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4 files changed, 20 insertions(+), 1 deletion(-)
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diff --git a/Makefile.am b/Makefile.am
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index e905602..6604baa 100644
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--- a/Makefile.am
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+++ b/Makefile.am
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@@ -33,6 +33,10 @@ PSCI_CPU_ON := 0xc4000003
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endif
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PSCI_CPU_OFF := 0x84000002
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+if KEEP_EL
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+DEFINES += -DKEEP_EL
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+endif
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+
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COMMON_SRC := common/
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COMMON_OBJ := boot.o bakery_lock.o platform.o lib.o device_tree.o
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diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
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index 27b1139..c079d22 100644
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--- a/arch/aarch64/boot.S
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+++ b/arch/aarch64/boot.S
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@@ -254,7 +254,11 @@ el2_init:
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msr cnthctl_el2, x0
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isb
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+#ifdef KEEP_EL
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+ mov w0, #SPSR_KERNEL
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+#else
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mov w0, #SPSR_KERNEL_EL1
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+#endif
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ldr x1, =spsr_to_elx
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str w0, [x1]
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// fall through
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@@ -334,5 +338,5 @@ ASM_FUNC(jump_kernel)
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.align 3
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flag_keep_el:
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.long 0
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-spsr_to_elx:
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+ASM_DATA(spsr_to_elx)
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.long 0
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diff --git a/common/psci.c b/common/psci.c
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index a0e8700..945780b 100644
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--- a/common/psci.c
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+++ b/common/psci.c
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@@ -18,6 +18,8 @@
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#error "No MPIDRs provided"
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#endif
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+extern unsigned int spsr_to_elx;
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+
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static unsigned long branch_table[NR_CPUS];
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bakery_ticket_t branch_table_lock[NR_CPUS];
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@@ -44,6 +46,10 @@ static int psci_cpu_on(unsigned long target_mpidr, unsigned long address)
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ret = psci_store_address(cpu, address);
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bakery_unlock(branch_table_lock, this_cpu);
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+#ifdef KEEP_EL
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+ spsr_to_elx = SPSR_KERNEL_EL1;
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+#endif
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+
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return ret;
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}
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diff --git a/configure.ac b/configure.ac
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index 53e51be..0e07db3 100644
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--- a/configure.ac
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+++ b/configure.ac
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@@ -25,6 +25,11 @@ AS_IF([test "x$BOOTWRAPPER_ES" = x32 -a "x$KERNEL_ES" != x32],
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[AC_MSG_ERROR([a 32-bit boot-wrapper cannot launch a 64-bit kernel])]
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)
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+AC_ARG_ENABLE([keep-el],
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+ AC_HELP_STRING([--enable-keep-el], [keep exception level when start kernel]),
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+ [KEEP_EL=yes], [KEEP_EL=no])
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+AM_CONDITIONAL([KEEP_EL], [test "x$KEEP_EL" = xyes])
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+
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# Allow a user to pass --with-kernel-dir
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AC_ARG_WITH([kernel-dir],
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AS_HELP_STRING([--with-kernel-dir], [specify the root Linux kernel build directory (required)]),
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