* [PATCH 2/4] powerpc: Add relocation code for fixups
2013-12-23 1:24 [PATCH 0/4] powerpc: Enable ILE on pSeries without H_MODE_SET Alexander Graf
2013-12-23 1:24 ` [PATCH 1/4] powerpc: Add global exports for all interrupt vectors Alexander Graf
@ 2013-12-23 1:24 ` Alexander Graf
2013-12-23 1:24 ` [PATCH 3/4] powerpc: Add hack to make ppc64le work on hosts without ILE Alexander Graf
2013-12-23 1:24 ` [PATCH 4/4] powerpc: Don't return to BE mode when we are already there Alexander Graf
3 siblings, 0 replies; 5+ messages in thread
From: Alexander Graf @ 2013-12-23 1:24 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Dinar Valeev, Anton Blanchard
We need to patch an instruction that is covered by the fixup
framework. If we don't do anything about it we end up getting
our own patched instruction unpatched by nops by the fixups.
So add an export to the fixup code that allows us to tell it
that an instruction moved location in memory. This works because
we move the instruction into a different location, but still
execute it.
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/include/asm/cputable.h | 2 ++
arch/powerpc/lib/feature-fixups.c | 22 ++++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 0d4939b..c981f99 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -99,6 +99,8 @@ extern unsigned int __start___ftr_fixup, __stop___ftr_fixup;
extern struct cpu_spec *identify_cpu(unsigned long offset, unsigned int pvr);
extern void do_feature_fixups(unsigned long value, void *fixup_start,
void *fixup_end);
+extern void relocate_fixup_entry(void *fixup_start, void *fixup_end,
+ void *old_addr, void *new_addr);
extern const char *powerpc_base_platform;
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 7a8a748..33996a4 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -151,6 +151,28 @@ void do_final_fixups(void)
#endif
}
+/*
+ * This changes the internal fixup location of a code block from
+ * old_addr to new_addr.
+ */
+void relocate_fixup_entry(void *fixup_start, void *fixup_end,
+ void *old_addr, void *new_addr)
+{
+ struct fixup_entry *fcur, *fend;
+
+ fcur = fixup_start;
+ fend = fixup_end;
+
+ for (; fcur < fend; fcur++) {
+ long diff = (long)new_addr -
+ (long)calc_addr(fcur, fcur->start_off);
+ if (calc_addr(fcur, fcur->start_off) == old_addr) {
+ fcur->start_off += diff;
+ fcur->end_off += diff;
+ }
+ }
+}
+
#ifdef CONFIG_FTR_FIXUP_SELFTEST
#define check(x) \
--
1.8.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 3/4] powerpc: Add hack to make ppc64le work on hosts without ILE
2013-12-23 1:24 [PATCH 0/4] powerpc: Enable ILE on pSeries without H_MODE_SET Alexander Graf
2013-12-23 1:24 ` [PATCH 1/4] powerpc: Add global exports for all interrupt vectors Alexander Graf
2013-12-23 1:24 ` [PATCH 2/4] powerpc: Add relocation code for fixups Alexander Graf
@ 2013-12-23 1:24 ` Alexander Graf
2013-12-23 1:24 ` [PATCH 4/4] powerpc: Don't return to BE mode when we are already there Alexander Graf
3 siblings, 0 replies; 5+ messages in thread
From: Alexander Graf @ 2013-12-23 1:24 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Dinar Valeev, Anton Blanchard
Some hypervisors don't implement the H_SET_MODE hypercall that we
need to set the ILE bit in LPCR which allows us to execute interrupts
in little endian mode.
However otherwise we would be able to run on those hypervisors just
fine.
So let's be creative. This patch creates a few small helpers that
work without register clobbering that execute in big endian mode.
Every interrupt gets patched with a branch instruction as the first
instruction which jumps into their respective helper. That helper
enables MSR.LE and returns back to the original interrupt.
That way we can keep our interrupt handlers in little endian code
while the hypervisor is unaware that we need them to be in little
endian.
Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/kernel/Makefile | 3 +
arch/powerpc/kernel/fake_ile.S | 101 +++++++++++++++++++++++++++++++++
arch/powerpc/kernel/vmlinux.lds.S | 14 +++++
arch/powerpc/platforms/pseries/setup.c | 50 ++++++++++++++++
4 files changed, 168 insertions(+)
create mode 100644 arch/powerpc/kernel/fake_ile.S
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 445cb6e..31842e6 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -131,6 +131,9 @@ endif
obj-$(CONFIG_EPAPR_PARAVIRT) += epapr_paravirt.o epapr_hcalls.o
obj-$(CONFIG_KVM_GUEST) += kvm.o kvm_emul.o
+ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
+obj-$(CONFIG_PPC_BOOK3S_64) += fake_ile.o
+endif
# Disable GCOV in odd or sensitive code
GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/fake_ile.S b/arch/powerpc/kernel/fake_ile.S
new file mode 100644
index 0000000..21e9bd7
--- /dev/null
+++ b/arch/powerpc/kernel/fake_ile.S
@@ -0,0 +1,101 @@
+/*
+ * PowerPC helpers for hypervisors without ILE implementation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright SUSE Linux Products GmbH 2013
+ *
+ * Authors: Alexander Graf <agraf@suse.de>
+ */
+
+#include <asm/reg.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/exception-64s.h>
+
+/* Little Endian fixups for hosts that don't support Little Endian */
+
+#define FAKE_ILE_HANDLER(handler, area) \
+ \
+/* This runs in BE mode */ \
+fake_ile_##handler: \
+ .section __be_patch,"a" ;\
+ .llong fake_ile_##handler ;\
+ .previous ;\
+ SET_SCRATCH0(r13) ;\
+ GET_PACA(r13) ;\
+ std r9, area + EX_R9(r13) ;\
+ std r10, area + EX_R10(r13) ;\
+ mfsrr0 r9 ;\
+ mfsrr1 r10 ;\
+ std r9, area + EX_SRR0(r13) ;\
+ std r10, area + EX_R11(r13) ;\
+ mflr r9 ;\
+ bl 1f ;\
+ 1: ;\
+ mflr r10 ;\
+ mtlr r9 ;\
+ addi r9, r10, back_to_interrupt_##handler - 1b ;\
+ mfmsr r10 ;\
+ ori r10, r10, MSR_LE ;\
+ mtsrr0 r9 ;\
+ mtsrr1 r10 ;\
+ ld r9, area + EX_SRR0(r13) ;\
+ ld r10, area + EX_R11(r13) ;\
+ RFI ;\
+ end_fake_ile_##handler: ;\
+ .section __be_patch,"a" ;\
+ .llong end_fake_ile_##handler ;\
+ .previous ;\
+ ;\
+/* This runs in LE mode */ \
+back_to_interrupt_##handler: ;\
+ mtsrr0 r9 ;\
+ mtsrr1 r10 ;\
+ li r9, area + EX_R9 ;\
+ li r10, area + EX_R10 ;\
+ ldbrx r9, r13, r9 ;\
+ ldbrx r10, r13, r10 ;\
+ GET_SCRATCH0(r13) ;\
+ /* This becomes the instruction we patched away */ \
+ patched_insn_##handler: ;\
+ .long 0 ;\
+ b handler + 4 ;\
+ \
+ .section __fake_ile,"a" ;\
+ .llong handler ;\
+ .llong patched_insn_##handler ;\
+ .llong fake_ile_##handler ;\
+ .previous ;\
+
+FAKE_ILE_HANDLER(system_reset_pSeries, PACA_EXMC)
+FAKE_ILE_HANDLER(machine_check_pSeries_1, PACA_EXMC)
+FAKE_ILE_HANDLER(data_access_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(data_access_slb_pSeries, PACA_EXSLB)
+FAKE_ILE_HANDLER(instruction_access_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(instruction_access_slb_pSeries, PACA_EXSLB)
+FAKE_ILE_HANDLER(hardware_interrupt_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(alignment_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(program_check_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(fp_unavailable_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(decrementer_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(doorbell_super_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(trap_0b_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(system_call_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(performance_monitor_pseries_trampoline, PACA_EXGEN)
+FAKE_ILE_HANDLER(altivec_unavailable_pseries_trampoline, PACA_EXGEN)
+FAKE_ILE_HANDLER(vsx_unavailable_pseries_trampoline, PACA_EXGEN)
+FAKE_ILE_HANDLER(facility_unavailable_trampoline, PACA_EXGEN)
+FAKE_ILE_HANDLER(instruction_breakpoint_pSeries, PACA_EXGEN)
+FAKE_ILE_HANDLER(altivec_assist_pSeries, PACA_EXGEN)
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index f096e72..7fdb7c9 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -147,6 +147,20 @@ SECTIONS
*(__fw_ftr_fixup)
__stop___fw_ftr_fixup = .;
}
+
+ . = ALIGN(8);
+ __fake_ile : AT(ADDR(__fake_ile) - LOAD_OFFSET) {
+ __start___fake_ile = .;
+ *(__fake_ile)
+ __stop___fake_ile = .;
+ }
+
+ . = ALIGN(8);
+ __be_patch : AT(ADDR(__be_patch) - LOAD_OFFSET) {
+ __start___be_patch = .;
+ *(__be_patch)
+ __stop___be_patch = .;
+ }
#endif
.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
INIT_RAM_FS
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index c1f1908..fb5d98c 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -67,6 +67,9 @@
#include <asm/eeh.h>
#include <asm/reg.h>
#include <asm/plpar_wrappers.h>
+#include <asm/cacheflush.h>
+#include <asm/cputable.h>
+#include <asm/code-patching.h>
#include "pseries.h"
@@ -455,6 +458,40 @@ long pseries_big_endian_exceptions(void)
}
}
+static void swizzle_endian(u32 *start, u32 *end)
+{
+ for (; (long)start < (long)end; start++)
+ patch_instruction(start, swab32(*start));
+}
+
+static void fixup_missing_little_endian_exceptions(void)
+{
+ extern u32 *__start___fake_ile, *__stop___fake_ile;
+ extern u32 *__start___be_patch, *__stop___be_patch;
+ u32 **be_table = &__start___be_patch;
+ u32 **fake_table = &__start___fake_ile;
+
+ /* Make our big endian code look like big endian code */
+ for (; (long)be_table < (long)&__stop___be_patch; be_table += 2)
+ swizzle_endian(be_table[0], be_table[1]);
+
+ /* Now patch the interrupt handlers to branch to our BE code */
+ for (; (long)fake_table < (long)&__stop___fake_ile; fake_table += 3) {
+ u32 *le_handler = fake_table[0];
+ u32 *patched_insn = fake_table[1];
+ u32 *be_handler = fake_table[2];
+ u32 le_be_diff = (long)be_handler - (long)le_handler;
+ patch_instruction(patched_insn, *le_handler);
+ /* This patches the interrupt handler's first instruction into
+ a branch that jumps to our BE handler that enables MSR_LE */
+ patch_instruction(le_handler, swab32(0x48000000 | le_be_diff));
+ /* Make sure that feature fixups use the new address for its
+ code patching */
+ relocate_fixup_entry(&__start___ftr_fixup, &__stop___ftr_fixup,
+ le_handler, patched_insn);
+ }
+}
+
static long pseries_little_endian_exceptions(void)
{
long rc;
@@ -737,6 +774,19 @@ static int __init pSeries_probe(void)
ppc_md.progress("H_SET_MODE LE exception fail", 0);
panic("Could not enable little endian exceptions");
}
+ } else {
+ /*
+ * The hypervisor we're running on does not know how to
+ * configure us to run interrupts in little endian mode,
+ * so we have to cheat a bit.
+ *
+ * This call reprograms all interrupt handlers' first
+ * instruction into a branch to a big endian fixup section
+ * which only transitions us into little endian mode, then
+ * returns back to the normal little endian interrupt
+ * handler.
+ */
+ fixup_missing_little_endian_exceptions();
}
#endif
--
1.8.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread