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extable relies on the MMU to work properly, so it's useless to
include __ex_table sections and build extable related functions for
!MMU case.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/r/20230509152641.805-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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This config allows to compile 64b kernel as PIE and to relocate it at
any virtual address at runtime: this paves the way to KASLR.
Runtime relocation is possible since relocation metadata are embedded into
the kernel.
Note that relocating at runtime introduces an overhead even if the
kernel is loaded at the same address it was linked at and that the compiler
options are those used in arm64 which uses the same RELA relocation
format.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230329045329.64565-4-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Anup Patel <apatel@ventanamicro.com> says:
The Linux NVDIMM PEM drivers require arch support to map and access the
persistent memory device. This series adds RISC-V PMEM support using
recently added Svpbmt and Zicbom support.
* b4-shazam-merge:
RISC-V: Enable PMEM drivers
RISC-V: Implement arch specific PMEM APIs
RISC-V: Fix MEMREMAP_WB for systems with Svpbmt
Link: https://lore.kernel.org/r/20221114090536.1662624-1-apatel@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The NVDIMM PMEM driver expects arch specific APIs for cache maintenance
and if arch does not provide these APIs then NVDIMM PMEM driver will
always use MEMREMAP_WT to map persistent memory which in-turn maps as
UC memory type defined by the RISC-V Svpbmt specification.
Now that the Svpbmt and Zicbom support is available in RISC-V kernel,
we implement PMEM APIs using ALT_CMO_OP() macros so that the NVDIMM
PMEM driver can use MEMREMAP_WB to map persistent memory.
Co-developed-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221114090536.1662624-3-apatel@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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This sets the HAVE_ARCH_HUGE_VMAP option, and defines the required page
table functions. With this feature, ioremap area will be mapped with
huge page granularity according to its actual size. This feature can be
disabled by kernel parameter "nohugeiomap".
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Tested-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20221012120038.1034354-2-liushixin2@huawei.com
[Palmer: minor formatting]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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The Zicbom ISA-extension was ratified in november 2021
and introduces instructions for dcache invalidate, clean
and flush operations.
Implement cache management operations for non-coherent devices
based on them.
Of course not all cores will support this, so implement an
alternative-based mechanism that replaces empty instructions
with ones done around Zicbom instructions.
As discussed in previous versions, assume the platform
being coherent by default so that non-coherent devices need
to get marked accordingly by firmware.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220706231536.2041855-4-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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__virt_to_phys function is called very early in the boot process (ie
kasan_early_init) so it should not be instrumented by KASAN otherwise it
bugs.
Fix this by declaring phys_addr.c as non-kasan instrumentable.
Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Fixes: 8ad8b72721d0 (riscv: Add KASAN support)
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Just like arm64, we can't trace the function in the patch_text path.
Here is the bug log:
[ 45.234334] Unable to handle kernel paging request at virtual address ffffffd38ae80900
[ 45.242313] Oops [#1]
[ 45.244600] Modules linked in:
[ 45.247678] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.9.0-00025-g9b7db83-dirty #215
[ 45.255797] epc: ffffffe00021689a ra : ffffffe00021718e sp : ffffffe01afabb58
[ 45.262955] gp : ffffffe00136afa0 tp : ffffffe01af94d00 t0 : 0000000000000002
[ 45.270200] t1 : 0000000000000000 t2 : 0000000000000001 s0 : ffffffe01afabc08
[ 45.277443] s1 : ffffffe0013718a8 a0 : 0000000000000000 a1 : ffffffe01afabba8
[ 45.284686] a2 : 0000000000000000 a3 : 0000000000000000 a4 : c4c16ad38ae80900
[ 45.291929] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000052464e43
[ 45.299173] s2 : 0000000000000001 s3 : ffffffe000206a60 s4 : ffffffe000206a60
[ 45.306415] s5 : 00000000000009ec s6 : ffffffe0013718a8 s7 : c4c16ad38ae80900
[ 45.313658] s8 : 0000000000000004 s9 : 0000000000000001 s10: 0000000000000001
[ 45.320902] s11: 0000000000000003 t3 : 0000000000000001 t4 : ffffffffd192fe79
[ 45.328144] t5 : ffffffffb8f80000 t6 : 0000000000040000
[ 45.333472] status: 0000000200000100 badaddr: ffffffd38ae80900 cause: 000000000000000f
[ 45.341514] ---[ end trace d95102172248fdcf ]---
[ 45.346176] note: migration/0[11] exited with preempt_count 1
(gdb) x /2i $pc
=> 0xffffffe00021689a <__do_proc_dointvec+196>: sd zero,0(s7)
0xffffffe00021689e <__do_proc_dointvec+200>: li s11,0
(gdb) bt
0 __do_proc_dointvec (tbl_data=0x0, table=0xffffffe01afabba8,
write=0, buffer=0x0, lenp=0x7bf897061f9a0800, ppos=0x4, conv=0x0,
data=0x52464e43) at kernel/sysctl.c:581
1 0xffffffe00021718e in do_proc_dointvec (data=<optimized out>,
conv=<optimized out>, ppos=<optimized out>, lenp=<optimized out>,
buffer=<optimized out>, write=<optimized out>, table=<optimized out>)
at kernel/sysctl.c:964
2 proc_dointvec_minmax (ppos=<optimized out>, lenp=<optimized out>,
buffer=<optimized out>, write=<optimized out>, table=<optimized out>)
at kernel/sysctl.c:964
3 proc_do_static_key (table=<optimized out>, write=1, buffer=0x0,
lenp=0x0, ppos=0x7bf897061f9a0800) at kernel/sysctl.c:1643
4 0xffffffe000206792 in ftrace_make_call (rec=<optimized out>,
addr=<optimized out>) at arch/riscv/kernel/ftrace.c:109
5 0xffffffe0002c9c04 in __ftrace_replace_code
(rec=0xffffffe01ae40c30, enable=3) at kernel/trace/ftrace.c:2503
6 0xffffffe0002ca0b2 in ftrace_replace_code (mod_flags=<optimized
out>) at kernel/trace/ftrace.c:2530
7 0xffffffe0002ca26a in ftrace_modify_all_code (command=5) at
kernel/trace/ftrace.c:2677
8 0xffffffe0002ca30e in __ftrace_modify_code (data=<optimized out>)
at kernel/trace/ftrace.c:2703
9 0xffffffe0002c13b0 in multi_cpu_stop (data=0x0) at kernel/stop_machine.c:224
10 0xffffffe0002c0fde in cpu_stopper_thread (cpu=<optimized out>) at
kernel/stop_machine.c:491
11 0xffffffe0002343de in smpboot_thread_fn (data=0x0) at kernel/smpboot.c:165
12 0xffffffe00022f8b4 in kthread (_create=0xffffffe01af0c040) at
kernel/kthread.c:292
13 0xffffffe000201fac in handle_exception () at arch/riscv/kernel/entry.S:236
0xffffffe00020678a <+114>: auipc ra,0xffffe
0xffffffe00020678e <+118>: jalr -118(ra) # 0xffffffe000204714 <patch_text_nosync>
0xffffffe000206792 <+122>: snez a0,a0
(gdb) disassemble patch_text_nosync
Dump of assembler code for function patch_text_nosync:
0xffffffe000204714 <+0>: addi sp,sp,-32
0xffffffe000204716 <+2>: sd s0,16(sp)
0xffffffe000204718 <+4>: sd ra,24(sp)
0xffffffe00020471a <+6>: addi s0,sp,32
0xffffffe00020471c <+8>: auipc ra,0x0
0xffffffe000204720 <+12>: jalr -384(ra) # 0xffffffe00020459c <patch_insn_write>
0xffffffe000204724 <+16>: beqz a0,0xffffffe00020472e <patch_text_nosync+26>
0xffffffe000204726 <+18>: ld ra,24(sp)
0xffffffe000204728 <+20>: ld s0,16(sp)
0xffffffe00020472a <+22>: addi sp,sp,32
0xffffffe00020472c <+24>: ret
0xffffffe00020472e <+26>: sd a0,-24(s0)
0xffffffe000204732 <+30>: auipc ra,0x4
0xffffffe000204736 <+34>: jalr -1464(ra) # 0xffffffe00020817a <flush_icache_all>
0xffffffe00020473a <+38>: ld a0,-24(s0)
0xffffffe00020473e <+42>: ld ra,24(sp)
0xffffffe000204740 <+44>: ld s0,16(sp)
0xffffffe000204742 <+46>: addi sp,sp,32
0xffffffe000204744 <+48>: ret
(gdb) disassemble flush_icache_all-4
Dump of assembler code for function flush_icache_all:
0xffffffe00020817a <+0>: addi sp,sp,-8
0xffffffe00020817c <+2>: sd ra,0(sp)
0xffffffe00020817e <+4>: auipc ra,0xfffff
0xffffffe000208182 <+8>: jalr -1822(ra) # 0xffffffe000206a60 <ftrace_caller>
0xffffffe000208186 <+12>: ld ra,0(sp)
0xffffffe000208188 <+14>: addi sp,sp,8
0xffffffe00020818a <+0>: addi sp,sp,-16
0xffffffe00020818c <+2>: sd s0,0(sp)
0xffffffe00020818e <+4>: sd ra,8(sp)
0xffffffe000208190 <+6>: addi s0,sp,16
0xffffffe000208192 <+8>: li a0,0
0xffffffe000208194 <+10>: auipc ra,0xfffff
0xffffffe000208198 <+14>: jalr -410(ra) # 0xffffffe000206ffa <sbi_remote_fence_i>
0xffffffe00020819c <+18>: ld s0,0(sp)
0xffffffe00020819e <+20>: ld ra,8(sp)
0xffffffe0002081a0 <+22>: addi sp,sp,16
0xffffffe0002081a2 <+24>: ret
(gdb) frame 5
(rec=0xffffffe01ae40c30, enable=3) at kernel/trace/ftrace.c:2503
2503 return ftrace_make_call(rec, ftrace_addr);
(gdb) p /x rec->ip
$2 = 0xffffffe00020817a -> flush_icache_all !
When we modified flush_icache_all's patchable-entry with ftrace_caller:
- Insert ftrace_caller at flush_icache_all prologue.
- Call flush_icache_all to sync I/Dcache, but flush_icache_all is
just we modified by half.
Link: https://lore.kernel.org/linux-riscv/CAJF2gTT=oDWesWe0JVWvTpGi60-gpbNhYLdFWN_5EbyeqoEDdw@mail.gmail.com/T/#t
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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We must use $(CC_FLAGS_FTRACE) instead of directly using -pg. It
will cause -fpatchable-function-entry error.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to the riscv Kconfig.
Also disable instrumentation of some early boot code and vdso.
Boot-tested on QEMU's riscv64 virt machine.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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In a similar manner to arm64, x86, powerpc, etc., it can traverse all
page tables, and dump the page table layout with the memory types and
permissions.
Add a debugfs file at /sys/kernel/debug/kernel_page_tables to export
the page table layout to userspace.
Signed-off-by: Zong Li <zong.li@sifive.com>
Tested-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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Add set_memory_ro/rw/x/nx architecture hooks to change the page
attribution.
Use own set_memory.h rather than generic set_memory.h
(i.e. include/asm-generic/set_memory.h), because we want to add other
function prototypes here.
Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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This patch implements CONFIG_DEBUG_VIRTUAL to do additional checks on
virt_to_phys and __pa_symbol calls. virt_to_phys used for linear mapping
check, and __pa_symbol used for kernel symbol check. In current RISC-V,
kernel image maps to linear mapping area. If CONFIG_DEBUG_VIRTUAL is
disable, these two functions calculate the offset on the address feded
directly without any checks.
The result of test_debug_virtual as follows:
[ 0.358456] ------------[ cut here ]------------
[ 0.358738] virt_to_phys used for non-linear address: (____ptrval____) (0xffffffd000000000)
[ 0.359174] WARNING: CPU: 0 PID: 1 at arch/riscv/mm/physaddr.c:16 __virt_to_phys+0x3c/0x50
[ 0.359409] Modules linked in:
[ 0.359630] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc3-00002-g5133c5c0ca13 #57
[ 0.359861] epc: ffffffe000253d1a ra : ffffffe000253d1a sp : ffffffe03aa87da0
[ 0.360019] gp : ffffffe000ae03b0 tp : ffffffe03aa88000 t0 : ffffffe000af2660
[ 0.360175] t1 : 0000000000000064 t2 : 00000000000000b7 s0 : ffffffe03aa87dc0
[ 0.360330] s1 : ffffffd000000000 a0 : 000000000000004f a1 : 0000000000000000
[ 0.360492] a2 : 0000000000000000 a3 : 0000000000000000 a4 : ffffffe000a84358
[ 0.360672] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000000000
[ 0.360876] s2 : ffffffe000ae0600 s3 : ffffffe00000fc7c s4 : ffffffe0000224b0
[ 0.361067] s5 : ffffffe000030890 s6 : ffffffe000022470 s7 : 0000000000000008
[ 0.361267] s8 : ffffffe0000002c4 s9 : ffffffe000ae0640 s10: ffffffe000ae0630
[ 0.361453] s11: 0000000000000000 t3 : 0000000000000000 t4 : 000000000001e6d0
[ 0.361636] t5 : ffffffe000ae0a18 t6 : ffffffe000aee54e
[ 0.361806] status: 0000000000000120 badaddr: 0000000000000000 cause: 0000000000000003
[ 0.362056] ---[ end trace aec0bf78d4978122 ]---
[ 0.362404] PA: 0xfffffff080200000 for VA: 0xffffffd000000000
[ 0.362607] PA: 0x00000000baddd2d0 for VA: 0xffffffe03abdd2d0
Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
Tested-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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This patch ports the feature Kernel Address SANitizer (KASAN).
Note: The start address of shadow memory is at the beginning of kernel
space, which is 2^64 - (2^39 / 2) in SV39. The size of the kernel space is
2^38 bytes so the size of shadow memory should be 2^38 / 8. Thus, the
shadow memory would not overlap with the fixmap area.
There are currently two limitations in this port,
1. RV64 only: KASAN need large address space for extra shadow memory
region.
2. KASAN can't debug the modules since the modules are allocated in VMALLOC
area. We mapped the shadow memory, which corresponding to VMALLOC area, to
the kasan_early_shadow_page because we don't have enough physical space for
all the shadow memory corresponding to VMALLOC area.
Signed-off-by: Nick Hu <nickhu@andestech.com>
Reported-by: Greentime Hu <green.hu@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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The sifive_l2_cache.c is in no way related to RISC-V architecture
memory management. It is a little stub driver working around the fact
that the EDAC maintainers prefer their drivers to be structured in a
certain way that doesn't fit the SiFive SOCs.
Move the file to drivers/soc and add a Kconfig option for it, as well
as the whole drivers/soc boilerplate for CONFIG_SOC_SIFIVE.
Fixes: a967a289f169 ("RISC-V: sifive_l2_cache: Add L2 cache controller driver for SiFive SoCs")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
[paul.walmsley@sifive.com: keep the MAINTAINERS change specific to the L2$ controller code]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
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Pull generic ioremap support from Christoph Hellwig:
"This adds the remaining bits for an entirely generic ioremap and
iounmap to lib/ioremap.c. To facilitate that, it cleans up the giant
mess of weird ioremap variants we had with no users outside the arch
code.
For now just the three newest ports use the code, but there is more
than a handful others that can be converted without too much work.
Summary:
- clean up various obsolete ioremap and iounmap variants
- add a new generic ioremap implementation and switch csky, nds32 and
riscv over to it"
* tag 'ioremap-5.5' of git://git.infradead.org/users/hch/ioremap: (21 commits)
nds32: use generic ioremap
csky: use generic ioremap
csky: remove ioremap_cache
riscv: use the generic ioremap code
lib: provide a simple generic ioremap implementation
sh: remove __iounmap
nios2: remove __iounmap
hexagon: remove __iounmap
m68k: rename __iounmap and mark it static
arch: rely on asm-generic/io.h for default ioremap_* definitions
asm-generic: don't provide ioremap for CONFIG_MMU
asm-generic: ioremap_uc should behave the same with and without MMU
xtensa: clean up ioremap
x86: Clean up ioremap()
parisc: remove __ioremap
nios2: remove __ioremap
alpha: remove the unused __ioremap wrapper
hexagon: clean up ioremap
ia64: rename ioremap_nocache to ioremap_uc
unicore32: remove ioremap_cached
...
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The kernel runs in M-mode without using page tables, and thus can't run
bare metal without help from additional firmware.
Most of the patch is just stubbing out code not needed without page
tables, but there is an interesting detail in the signals implementation:
- The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO
entry point, but the ELF VDSO is not supported for nommu Linux.
We instead copy the code to call the syscall onto the stack.
In addition to enabling the nommu code a new defconfig for a small
kernel image that can run in nommu mode on qemu is also provided, to run
a kernel in qemu you can use the following command line:
qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \
-kernel arch/riscv/boot/loader \
-drive file=rootfs.ext2,format=raw,id=hd0 \
-device virtio-blk-device,drive=hd0
Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards
around PCI_IOBASE definition to fix build issues; fixed checkpatch
issues; move the PCI_IO_* and VMEMMAP address space macros along
with the others; resolve sparse warning]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
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Use the generic ioremap code instead of providing a local version.
Note that this relies on the asm-generic no-op definition of
pgprot_noncached.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
Tested-by: Paul Walmsley <paul.walmsley@sifive.com> # rv32, rv64 boot
Acked-by: Paul Walmsley <paul.walmsley@sifive.com> # arch/riscv
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The TLB flush logic is going to become more complex. Start moving
it out of line.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
[paul.walmsley@sifive.com: fixed checkpatch whitespace warnings]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
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This patch implements both 4MB huge page support for 32bit kernel
and 2MB/1GB huge pages support for 64bit kernel.
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
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Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The driver currently supports only SiFive FU540-C000 platform.
The initial version of L2 cache controller driver includes:
- Initial configuration reporting at boot up.
- Support for ECC related functionality.
Signed-off-by: Yash Shah <yash.shah@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
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switch_mm is an expensive operations that has two users.
flush_icache_deferred is only called within switch_mm and can be moved
together. The function is expected to be more complicated when ASID
support is added, so clean up eagerly.
By moving them to a separate file we also removes some excessive
dependency of tlbflush.h and cacheflush.h.
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
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The Linux RISC-V 32bit kernel is broken after we moved setup_vm() from
kernel/setup.c to mm/init.c because Linux RISC-V 32bit kernel by default
uses cmodel=medlow which results in a non-position-independent setup_vm().
This patch fixes Linux RISC-V 32bit kernel booting by:
1. Forcing cmodel=medany for mm/init.c
2. Moving remaing MM-related stuff va_pa_offset, pfn_base and
empty_zero_page from kernel/setup.c to mm/init.c
Further, the setup_vm() cannot handle GCC instrumentation for FTRACE so
we disable it for mm/init.c by not using "-pg" compiler flag.
Fixes: 6f1e9e946f0b ("RISC-V: Move setup_vm() to mm/init.c")
Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
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The RISC-V ISA allows for instruction caches that are not coherent WRT
stores, even on a single hart. As a result, we need to explicitly flush
the instruction cache whenever marking a dirty page as executable in
order to preserve the correct system behavior.
Local instruction caches aren't that scary (our implementations actually
flush the cache, but RISC-V is defined to allow higher-performance
implementations to exist), but RISC-V defines no way to perform an
instruction cache shootdown. When explicitly asked to do so we can
shoot down remote instruction caches via an IPI, but this is a bit on
the slow side.
Instead of requiring an IPI to all harts whenever marking a page as
executable, we simply flush the currently running harts. In order to
maintain correct behavior, we additionally mark every other hart as
needing a deferred instruction cache which will be taken before anything
runs on it.
Signed-off-by: Andrew Waterman <andrew@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
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This patch contains all the build infrastructure that actually enables
the RISC-V port. This includes Makefiles, linker scripts, and Kconfig
files. It also contains the only top-level change, which adds RISC-V to
the list of architectures that need a sed run to produce the ARCH
variable when building locally.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
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