Re: [PATCH v6] RISC-V: enable XIP

From: Vitaly Wool
Date: Mon Apr 05 2021 - 04:34:57 EST

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In reply to: Vitaly Wool: "Re: [PATCH v6] RISC-V: enable XIP"
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On Sun, Apr 4, 2021 at 10:39 AM Vitaly Wool <vitaly.wool@xxxxxxxxxxxx> wrote:
>
> On Sat, Apr 3, 2021 at 12:00 PM Alex Ghiti <alex@xxxxxxxx> wrote:
> >
> > Hi Vitaly,
> >
> > Le 4/1/21 à 7:10 AM, Alex Ghiti a écrit :
> > > Le 4/1/21 à 4:52 AM, Vitaly Wool a écrit :
> > >> Hi Alex,
> > >>
> > >> On Thu, Apr 1, 2021 at 10:11 AM Alex Ghiti <alex@xxxxxxxx> wrote:
> > >>>
> > >>> Hi,
> > >>>
> > >>> Le 3/30/21 à 4:04 PM, Alex Ghiti a écrit :
> > >>>> Le 3/30/21 à 3:33 PM, Palmer Dabbelt a écrit :
> > >>>>> On Tue, 30 Mar 2021 11:39:10 PDT (-0700), alex@xxxxxxxx wrote:
> > >>>>>>
> > >>>>>>
> > >>>>>> Le 3/30/21 à 2:26 AM, Vitaly Wool a écrit :
> > >>>>>>> On Tue, Mar 30, 2021 at 8:23 AM Palmer Dabbelt
> > >>>>>>> <palmerdabbelt@xxxxxxxxxx> wrote:
> > >>>>>>>>
> > >>>>>>>> On Sun, 21 Mar 2021 17:12:15 PDT (-0700), vitaly.wool@xxxxxxxxxxxx
> > >>>>>>>> wrote:
> > >>>>>>>>> Introduce XIP (eXecute In Place) support for RISC-V platforms.
> > >>>>>>>>> It allows code to be executed directly from non-volatile storage
> > >>>>>>>>> directly addressable by the CPU, such as QSPI NOR flash which can
> > >>>>>>>>> be found on many RISC-V platforms. This makes way for significant
> > >>>>>>>>> optimization of RAM footprint. The XIP kernel is not compressed
> > >>>>>>>>> since it has to run directly from flash, so it will occupy more
> > >>>>>>>>> space on the non-volatile storage. The physical flash address used
> > >>>>>>>>> to link the kernel object files and for storing it has to be known
> > >>>>>>>>> at compile time and is represented by a Kconfig option.
> > >>>>>>>>>
> > >>>>>>>>> XIP on RISC-V will for the time being only work on MMU-enabled
> > >>>>>>>>> kernels.
> > >>>>>>>>>
> > >>>>>>>>> Signed-off-by: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
> > >>>>>>>>>
> > >>>>>>>>> ---
> > >>>>>>>>>
> > >>>>>>>>> Changes in v2:
> > >>>>>>>>> - dedicated macro for XIP address fixup when MMU is not enabled
> > >>>>>>>>> yet
> > >>>>>>>>> o both for 32-bit and 64-bit RISC-V
> > >>>>>>>>> - SP is explicitly set to a safe place in RAM before
> > >>>>>>>>> __copy_data call
> > >>>>>>>>> - removed redundant alignment requirements in vmlinux-xip.lds.S
> > >>>>>>>>> - changed long -> uintptr_t typecast in __XIP_FIXUP macro.
> > >>>>>>>>> Changes in v3:
> > >>>>>>>>> - rebased against latest for-next
> > >>>>>>>>> - XIP address fixup macro now takes an argument
> > >>>>>>>>> - SMP related fixes
> > >>>>>>>>> Changes in v4:
> > >>>>>>>>> - rebased against the current for-next
> > >>>>>>>>> - less #ifdef's in C/ASM code
> > >>>>>>>>> - dedicated XIP_FIXUP_OFFSET assembler macro in head.S
> > >>>>>>>>> - C-specific definitions moved into #ifndef __ASSEMBLY__
> > >>>>>>>>> - Fixed multi-core boot
> > >>>>>>>>> Changes in v5:
> > >>>>>>>>> - fixed build error for non-XIP kernels
> > >>>>>>>>> Changes in v6:
> > >>>>>>>>> - XIP_PHYS_RAM_BASE config option renamed to PHYS_RAM_BASE
> > >>>>>>>>> - added PHYS_RAM_BASE_FIXED config flag to allow usage of
> > >>>>>>>>> PHYS_RAM_BASE in non-XIP configurations if needed
> > >>>>>>>>> - XIP_FIXUP macro rewritten with a tempoarary variable to avoid
> > >>>>>>>>> side
> > >>>>>>>>> effects
> > >>>>>>>>> - fixed crash for non-XIP kernels that don't use built-in DTB
> > >>>>>>>>
> > >>>>>>>> So v5 landed on for-next, which generally means it's best to avoid
> > >>>>>>>> re-spinning the patch and instead send along fixups. That said,
> > >>>>>>>> the v5
> > >>>>>>>> is causing some testing failures for me.
> > >>>>>>>>
> > >>>>>>>> I'm going to drop the v5 for now as I don't have time to test this
> > >>>>>>>> tonight. I'll try and take a look soon, as it will conflict with
> > >>>>>>>> Alex's
> > >>>>>>>> patches.
> > >>>>>>>
> > >>>>>>> I can come up with the incremental patch instead pretty much
> > >>>>>>> straight
> > >>>>>>> away if that works better.
> > >>>>>>>
> > >>>>>>> ~Vitaly
> > >>>>>>>
> > >>>>>>>>> arch/riscv/Kconfig | 49 ++++++++++-
> > >>>>>>>>> arch/riscv/Makefile | 8 +-
> > >>>>>>>>> arch/riscv/boot/Makefile | 13 +++
> > >>>>>>>>> arch/riscv/include/asm/pgtable.h | 65 ++++++++++++--
> > >>>>>>>>> arch/riscv/kernel/cpu_ops_sbi.c | 11 ++-
> > >>>>>>>>> arch/riscv/kernel/head.S | 49 ++++++++++-
> > >>>>>>>>> arch/riscv/kernel/head.h | 3 +
> > >>>>>>>>> arch/riscv/kernel/setup.c | 8 +-
> > >>>>>>>>> arch/riscv/kernel/vmlinux-xip.lds.S | 132
> > >>>>>>>>> ++++++++++++++++++++++++++++
> > >>>>>>>>> arch/riscv/kernel/vmlinux.lds.S | 6 ++
> > >>>>>>>>> arch/riscv/mm/init.c | 100 +++++++++++++++++++--
> > >>>>>>>>> 11 files changed, 426 insertions(+), 18 deletions(-)
> > >>>>>>>>> create mode 100644 arch/riscv/kernel/vmlinux-xip.lds.S
> > >>>>>>>>>
> > >>>>>>>>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > >>>>>>>>> index 8ea60a0a19ae..bd6f82240c34 100644
> > >>>>>>>>> --- a/arch/riscv/Kconfig
> > >>>>>>>>> +++ b/arch/riscv/Kconfig
> > >>>>>>>>> @@ -441,7 +441,7 @@ config EFI_STUB
> > >>>>>>>>>
> > >>>>>>>>> config EFI
> > >>>>>>>>> bool "UEFI runtime support"
> > >>>>>>>>> - depends on OF
> > >>>>>>>>> + depends on OF && !XIP_KERNEL
> > >>>>>>>>> select LIBFDT
> > >>>>>>>>> select UCS2_STRING
> > >>>>>>>>> select EFI_PARAMS_FROM_FDT
> > >>>>>>>>> @@ -465,11 +465,56 @@ config STACKPROTECTOR_PER_TASK
> > >>>>>>>>> def_bool y
> > >>>>>>>>> depends on STACKPROTECTOR && CC_HAVE_STACKPROTECTOR_TLS
> > >>>>>>>>>
> > >>>>>>>>> +config PHYS_RAM_BASE_FIXED
> > >>>>>>>>> + bool "Explicitly specified physical RAM address"
> > >>>>>>>>> + default n
> > >>>>>>>>> +
> > >>>>>>>>> +config PHYS_RAM_BASE
> > >>>>>>>>> + hex "Platform Physical RAM address"
> > >>>>>>>>> + depends on PHYS_RAM_BASE_FIXED
> > >>>>>>>>> + default "0x80000000"
> > >>>>>>>>> + help
> > >>>>>>>>> + This is the physical address of RAM in the system. It has
> > >>>>>>>>> to be
> > >>>>>>>>> + explicitly specified to run early relocations of
> > >>>>>>>>> read-write data
> > >>>>>>>>> + from flash to RAM.
> > >>>>>>>>> +
> > >>>>>>>>> +config XIP_KERNEL
> > >>>>>>>>> + bool "Kernel Execute-In-Place from ROM"
> > >>>>>>>>> + depends on MMU
> > >>>>>>>>> + select PHYS_RAM_BASE_FIXED
> > >>>>>>>>> + help
> > >>>>>>>>> + Execute-In-Place allows the kernel to run from
> > >>>>>>>>> non-volatile storage
> > >>>>>>>>> + directly addressable by the CPU, such as NOR flash. This
> > >>>>>>>>> saves RAM
> > >>>>>>>>> + space since the text section of the kernel is not loaded
> > >>>>>>>>> from flash
> > >>>>>>>>> + to RAM. Read-write sections, such as the data section and
> > >>>>>>>>> stack,
> > >>>>>>>>> + are still copied to RAM. The XIP kernel is not compressed
> > >>>>>>>>> since
> > >>>>>>>>> + it has to run directly from flash, so it will take more
> > >>>>>>>>> space to
> > >>>>>>>>> + store it. The flash address used to link the kernel
> > >>>>>>>>> object files,
> > >>>>>>>>> + and for storing it, is configuration dependent. Therefore,
> > >>>>>>>>> if you
> > >>>>>>>>> + say Y here, you must know the proper physical address
> > >>>>>>>>> where to
> > >>>>>>>>> + store the kernel image depending on your own flash memory
> > >>>>>>>>> usage.
> > >>>>>>>>> +
> > >>>>>>>>> + Also note that the make target becomes "make xipImage"
> > >>>>>>>>> rather than
> > >>>>>>>>> + "make zImage" or "make Image". The final kernel binary to
> > >>>>>>>>> put in
> > >>>>>>>>> + ROM memory will be arch/riscv/boot/xipImage.
> > >>>>>>>>> +
> > >>>>>>>>> + If unsure, say N.
> > >>>>>>>>> +
> > >>>>>>>>> +config XIP_PHYS_ADDR
> > >>>>>>>>> + hex "XIP Kernel Physical Location"
> > >>>>>>>>> + depends on XIP_KERNEL
> > >>>>>>>>> + default "0x21000000"
> > >>>>>>>>> + help
> > >>>>>>>>> + This is the physical address in your flash memory the
> > >>>>>>>>> kernel will
> > >>>>>>>>> + be linked for and stored to. This address is dependent on
> > >>>>>>>>> your
> > >>>>>>>>> + own flash usage.
> > >>>>>>>>> +
> > >>>>>>>>> endmenu
> > >>>>>>>>>
> > >>>>>>>>> config BUILTIN_DTB
> > >>>>>>>>> - def_bool n
> > >>>>>>>>> + bool
> > >>>>>>>>> depends on OF
> > >>>>>>>>> + default y if XIP_KERNEL
> > >>>>>>>>>
> > >>>>>>>>> menu "Power management options"
> > >>>>>>>>>
> > >>>>>>>>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
> > >>>>>>>>> index 1368d943f1f3..8fcbec03974d 100644
> > >>>>>>>>> --- a/arch/riscv/Makefile
> > >>>>>>>>> +++ b/arch/riscv/Makefile
> > >>>>>>>>> @@ -82,7 +82,11 @@ CHECKFLAGS += -D__riscv -D__riscv_xlen=$(BITS)
> > >>>>>>>>>
> > >>>>>>>>> # Default target when executing plain make
> > >>>>>>>>> boot := arch/riscv/boot
> > >>>>>>>>> +ifeq ($(CONFIG_XIP_KERNEL),y)
> > >>>>>>>>> +KBUILD_IMAGE := $(boot)/xipImage
> > >>>>>>>>> +else
> > >>>>>>>>> KBUILD_IMAGE := $(boot)/Image.gz
> > >>>>>>>>> +endif
> > >>>>>>>>>
> > >>>>>>>>> head-y := arch/riscv/kernel/head.o
> > >>>>>>>>>
> > >>>>>>>>> @@ -95,12 +99,14 @@ PHONY += vdso_install
> > >>>>>>>>> vdso_install:
> > >>>>>>>>> $(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso $@
> > >>>>>>>>>
> > >>>>>>>>> +ifneq ($(CONFIG_XIP_KERNEL),y)
> > >>>>>>>>> ifeq ($(CONFIG_RISCV_M_MODE)$(CONFIG_SOC_CANAAN),yy)
> > >>>>>>>>> KBUILD_IMAGE := $(boot)/loader.bin
> > >>>>>>>>> else
> > >>>>>>>>> KBUILD_IMAGE := $(boot)/Image.gz
> > >>>>>>>>> endif
> > >>>>>>>>> -BOOT_TARGETS := Image Image.gz loader loader.bin
> > >>>>>>>>> +endif
> > >>>>>>>>> +BOOT_TARGETS := Image Image.gz loader loader.bin xipImage
> > >>>>>>>>>
> > >>>>>>>>> all: $(notdir $(KBUILD_IMAGE))
> > >>>>>>>>>
> > >>>>>>>>> diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
> > >>>>>>>>> index 03404c84f971..6bf299f70c27 100644
> > >>>>>>>>> --- a/arch/riscv/boot/Makefile
> > >>>>>>>>> +++ b/arch/riscv/boot/Makefile
> > >>>>>>>>> @@ -17,8 +17,21 @@
> > >>>>>>>>> KCOV_INSTRUMENT := n
> > >>>>>>>>>
> > >>>>>>>>> OBJCOPYFLAGS_Image :=-O binary -R .note -R
> > >>>>>>>>> .note.gnu.build-id -R
> > >>>>>>>>> .comment -S
> > >>>>>>>>> +OBJCOPYFLAGS_xipImage :=-O binary -R .note -R .note.gnu.build-id
> > >>>>>>>>> -R .comment -S
> > >>>>>>>>>
> > >>>>>>>>> targets := Image Image.* loader loader.o loader.lds loader.bin
> > >>>>>>>>> +targets := Image Image.* loader loader.o loader.lds loader.bin
> > >>>>>>>>> xipImage
> > >>>>>>>>> +
> > >>>>>>>>> +ifeq ($(CONFIG_XIP_KERNEL),y)
> > >>>>>>>>> +
> > >>>>>>>>> +quiet_cmd_mkxip = $(quiet_cmd_objcopy)
> > >>>>>>>>> +cmd_mkxip = $(cmd_objcopy)
> > >>>>>>>>> +
> > >>>>>>>>> +$(obj)/xipImage: vmlinux FORCE
> > >>>>>>>>> + $(call if_changed,mkxip)
> > >>>>>>>>> + @$(kecho) ' Physical Address of xipImage:
> > >>>>>>>>> $(CONFIG_XIP_PHYS_ADDR)'
> > >>>>>>>>> +
> > >>>>>>>>> +endif
> > >>>>>>>>>
> > >>>>>>>>> $(obj)/Image: vmlinux FORCE
> > >>>>>>>>> $(call if_changed,objcopy)
> > >>>>>>>>> diff --git a/arch/riscv/include/asm/pgtable.h
> > >>>>>>>>> b/arch/riscv/include/asm/pgtable.h
> > >>>>>>>>> index ebf817c1bdf4..21a9b2f8d1c7 100644
> > >>>>>>>>> --- a/arch/riscv/include/asm/pgtable.h
> > >>>>>>>>> +++ b/arch/riscv/include/asm/pgtable.h
> > >>>>>>>>> @@ -11,6 +11,33 @@
> > >>>>>>>>>
> > >>>>>>>>> #include <asm/pgtable-bits.h>
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_MMU
> > >>>>>>>>> +
> > >>>>>>>>> +#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
> > >>>>>>>>> +
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +#define VMALLOC_SIZE ((KERN_VIRT_SIZE >> 1) - SZ_16M)
> > >>>>>>>>> +#define VMALLOC_END (PAGE_OFFSET - SZ_16M - 1)
> > >>>>>>>>> +
> > >>>>>>>>> +#define XIP_OFFSET SZ_8M
> > >>>>>>>>> +#define XIP_MASK (SZ_8M - 1)
> > >>>>>>>>> +#define XIP_VIRT_ADDR(physaddr) \
> > >>>>>>>>> + (PAGE_OFFSET - XIP_OFFSET + ((physaddr) & XIP_MASK))
> > >>>>>>>>> +
> > >>>>>>>>> +#else
> > >>>>>>>>> +
> > >>>>>>>>> +#define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
> > >>>>>>>>> +#define VMALLOC_END (PAGE_OFFSET - 1)
> > >>>>>>>>> +
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +
> > >>>>>>>>> +#else
> > >>>>>>>>> +
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +#define XIP_VIRT_ADDR(physaddr) (physaddr)
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +#endif /* CONFIG_MMU */
> > >>>>>>>>> +
> > >>>>>>>>> #ifndef __ASSEMBLY__
> > >>>>>>>>>
> > >>>>>>>>> /* Page Upper Directory not used in RISC-V */
> > >>>>>>>>> @@ -21,9 +48,25 @@
> > >>>>>>>>>
> > >>>>>>>>> #ifdef CONFIG_MMU
> > >>>>>>>>>
> > >>>>>>>>> -#define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
> > >>>>>>>>> -#define VMALLOC_END (PAGE_OFFSET - 1)
> > >>>>>>>>> -#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +/*
> > >>>>>>>>> + * Since we use sections to map it, this macro replaces the
> > >>>>>>>>> physical address
> > >>>>>>>>> + * with its virtual address while keeping offset from the base
> > >>>>>>>>> section.
> > >>>>>>>>> + */
> > >>>>>>>>> +#define XIP_PHYS_ADDR(va) \
> > >>>>>>>>> + ((uintptr_t)(va) - PAGE_OFFSET + XIP_OFFSET +
> > >>>>>>>>> CONFIG_XIP_PHYS_ADDR)
> > >>>>>>>>> +
> > >>>>>>>>> +#define XIP_VIRT_ADDR_START XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
> > >>>>>>>>> +
> > >>>>>>>>> +#define XIP_FIXUP(addr) ({ \
> > >>>>>>>>> + uintptr_t __a = (uintptr_t)(addr); \
> > >>>>>>>>> + (__a >= CONFIG_XIP_PHYS_ADDR && \
> > >>>>>>>>> + __a < CONFIG_XIP_PHYS_ADDR + SZ_16M) ? \
> > >>>>>>>>> + __a - CONFIG_XIP_PHYS_ADDR + CONFIG_PHYS_RAM_BASE -
> > >>>>>>>>> XIP_OFFSET : __a; \
> > >>>>>>>>> +})
> > >>>>>>>>> +#else
> > >>>>>>>>> +#define XIP_FIXUP(addr) (addr)
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>>
> > >>>>>>>>> #define BPF_JIT_REGION_SIZE (SZ_128M)
> > >>>>>>>>> #define BPF_JIT_REGION_START (PAGE_OFFSET -
> > >>>>>>>>> BPF_JIT_REGION_SIZE)
> > >>>>>>>>> @@ -484,8 +527,20 @@ static inline int
> > >>>>>>>>> ptep_clear_flush_young(struct vm_area_struct *vma,
> > >>>>>>>>>
> > >>>>>>>>> #define kern_addr_valid(addr) (1) /* FIXME */
> > >>>>>>>>>
> > >>>>>>>>> -extern void *dtb_early_va;
> > >>>>>>>>> -extern uintptr_t dtb_early_pa;
> > >>>>>>>>> +extern void *_dtb_early_va;
> > >>>>>>>>> +extern uintptr_t _dtb_early_pa;
> > >>>>>>>>> +#if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_MMU)
> > >>>>>>>>> +
> > >>>>>>>>> +#define dtb_early_va (*(void **)XIP_FIXUP(&_dtb_early_va))
> > >>>>>>>>> +#define dtb_early_pa (*(uintptr_t *)XIP_FIXUP(&_dtb_early_pa))
> > >>>>>>>>> +
> > >>>>>>>>> +#else
> > >>>>>>>>> +
> > >>>>>>>>> +#define dtb_early_va _dtb_early_va
> > >>>>>>>>> +#define dtb_early_pa _dtb_early_pa
> > >>>>>>>>> +
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +
> > >>>>>>>>> void setup_bootmem(void);
> > >>>>>>>>> void paging_init(void);
> > >>>>>>>>> void misc_mem_init(void);
> > >>>>>>>>> diff --git a/arch/riscv/kernel/cpu_ops_sbi.c
> > >>>>>>>>> b/arch/riscv/kernel/cpu_ops_sbi.c
> > >>>>>>>>> index 685fae72b7f5..2413c2997350 100644
> > >>>>>>>>> --- a/arch/riscv/kernel/cpu_ops_sbi.c
> > >>>>>>>>> +++ b/arch/riscv/kernel/cpu_ops_sbi.c
> > >>>>>>>>> @@ -53,10 +53,19 @@ static int sbi_hsm_hart_get_status(unsigned
> > >>>>>>>>> long hartid)
> > >>>>>>>>> }
> > >>>>>>>>> #endif
> > >>>>>>>>>
> > >>>>>>>>> +static inline unsigned long get_secondary_start_phys(void)
> > >>>>>>>>> +{
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + return XIP_PHYS_ADDR(secondary_start_sbi);
> > >>>>>>>>> +#else
> > >>>>>>>>> + return __pa_symbol(secondary_start_sbi);
> > >>>>>>>>> +#endif
> > >>>>>>>>> +}
> > >>>>>>>>> +
> > >>>>>>>>> static int sbi_cpu_start(unsigned int cpuid, struct task_struct
> > >>>>>>>>> *tidle)
> > >>>>>>>>> {
> > >>>>>>>>> int rc;
> > >>>>>>>>> - unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
> > >>>>>>>>> + unsigned long boot_addr = get_secondary_start_phys();
> > >>>>>>>>> int hartid = cpuid_to_hartid_map(cpuid);
> > >>>>>>>>>
> > >>>>>>>>> cpu_update_secondary_bootdata(cpuid, tidle);
> > >>>>>>>>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> > >>>>>>>>> index f5a9bad86e58..bbe74e37914f 100644
> > >>>>>>>>> --- a/arch/riscv/kernel/head.S
> > >>>>>>>>> +++ b/arch/riscv/kernel/head.S
> > >>>>>>>>> @@ -9,11 +9,23 @@
> > >>>>>>>>> #include <linux/linkage.h>
> > >>>>>>>>> #include <asm/thread_info.h>
> > >>>>>>>>> #include <asm/page.h>
> > >>>>>>>>> +#include <asm/pgtable.h>
> > >>>>>>>>> #include <asm/csr.h>
> > >>>>>>>>> #include <asm/hwcap.h>
> > >>>>>>>>> #include <asm/image.h>
> > >>>>>>>>> #include "efi-header.S"
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +.macro XIP_FIXUP_OFFSET reg
> > >>>>>>>>> + REG_L t0, _xip_fixup
> > >>>>>>>>> + add \reg, \reg, t0
> > >>>>>>>>> +.endm
> > >>>>>>>>> +_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR -
> > >>>>>>>>> XIP_OFFSET
> > >>>>>>>>> +#else
> > >>>>>>>>> +.macro XIP_FIXUP_OFFSET reg
> > >>>>>>>>> +.endm
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +
> > >>>>>>>>> __HEAD
> > >>>>>>>>> ENTRY(_start)
> > >>>>>>>>> /*
> > >>>>>>>>> @@ -69,7 +81,11 @@ pe_head_start:
> > >>>>>>>>> #ifdef CONFIG_MMU
> > >>>>>>>>> relocate:
> > >>>>>>>>> /* Relocate return address */
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + li a1, XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
> > >>>>>>>>> +#else
> > >>>>>>>>> li a1, PAGE_OFFSET
> > >>>>>>>>> +#endif
> > >>>>>>>>> la a2, _start
> > >>>>>>>>> sub a1, a1, a2
> > >>>>>>>>> add ra, ra, a1
> > >>>>>>>>> @@ -91,6 +107,7 @@ relocate:
> > >>>>>>>>> * to ensure the new translations are in use.
> > >>>>>>>>> */
> > >>>>>>>>> la a0, trampoline_pg_dir
> > >>>>>>>>> + XIP_FIXUP_OFFSET a0
> > >>>>>>>>> srl a0, a0, PAGE_SHIFT
> > >>>>>>>>> or a0, a0, a1
> > >>>>>>>>> sfence.vma
> > >>>>>>>>> @@ -144,7 +161,9 @@ secondary_start_sbi:
> > >>>>>>>>>
> > >>>>>>>>> slli a3, a0, LGREG
> > >>>>>>>>> la a4, __cpu_up_stack_pointer
> > >>>>>>>>> + XIP_FIXUP_OFFSET a4
> > >>>>>>>>> la a5, __cpu_up_task_pointer
> > >>>>>>>>> + XIP_FIXUP_OFFSET a5
> > >>>>>>>>> add a4, a3, a4
> > >>>>>>>>> add a5, a3, a5
> > >>>>>>>>> REG_L sp, (a4)
> > >>>>>>>>> @@ -156,6 +175,7 @@ secondary_start_common:
> > >>>>>>>>> #ifdef CONFIG_MMU
> > >>>>>>>>> /* Enable virtual memory and relocate to virtual
> > >>>>>>>>> address */
> > >>>>>>>>> la a0, swapper_pg_dir
> > >>>>>>>>> + XIP_FIXUP_OFFSET a0
> > >>>>>>>>> call relocate
> > >>>>>>>>> #endif
> > >>>>>>>>> call setup_trap_vector
> > >>>>>>>>> @@ -236,12 +256,33 @@ pmp_done:
> > >>>>>>>>> .Lgood_cores:
> > >>>>>>>>> #endif
> > >>>>>>>>>
> > >>>>>>>>> +#ifndef CONFIG_XIP_KERNEL
> > >>>>>>>>> /* Pick one hart to run the main boot sequence */
> > >>>>>>>>> la a3, hart_lottery
> > >>>>>>>>> li a2, 1
> > >>>>>>>>> amoadd.w a3, a2, (a3)
> > >>>>>>>>> bnez a3, .Lsecondary_start
> > >>>>>>>>>
> > >>>>>>>>> +#else
> > >>>>>>>>> + /* hart_lottery in flash contains a magic number */
> > >>>>>>>>> + la a3, hart_lottery
> > >>>>>>>>> + mv a2, a3
> > >>>>>>>>> + XIP_FIXUP_OFFSET a2
> > >>>>>>>>> + lw t1, (a3)
> > >>>>>>>>> + amoswap.w t0, t1, (a2)
> > >>>>>>>>> + /* first time here if hart_lottery in RAM is not set */
> > >>>>>>>>> + beq t0, t1, .Lsecondary_start
> > >>>>>>>>> +
> > >>>>>>>>> + la sp, _end + THREAD_SIZE
> > >>>>>>>>> + XIP_FIXUP_OFFSET sp
> > >>>>>>>>> + mv s0, a0
> > >>>>>>>>> + call __copy_data
> > >>>>>>>>> +
> > >>>>>>>>> + /* Restore a0 copy */
> > >>>>>>>>> + mv a0, s0
> > >>>>>>>>> +#endif
> > >>>>>>>>> +
> > >>>>>>>>> +#ifndef CONFIG_XIP_KERNEL
> > >>>>>>>>> /* Clear BSS for flat non-ELF images */
> > >>>>>>>>> la a3, __bss_start
> > >>>>>>>>> la a4, __bss_stop
> > >>>>>>>>> @@ -251,15 +292,18 @@ clear_bss:
> > >>>>>>>>> add a3, a3, RISCV_SZPTR
> > >>>>>>>>> blt a3, a4, clear_bss
> > >>>>>>>>> clear_bss_done:
> > >>>>>>>>> -
> > >>>>>>>>> +#endif
> > >>>>>>>>> /* Save hart ID and DTB physical address */
> > >>>>>>>>> mv s0, a0
> > >>>>>>>>> mv s1, a1
> > >>>>>>>>> +
> > >>>>>>>>> la a2, boot_cpu_hartid
> > >>>>>>>>> + XIP_FIXUP_OFFSET a2
> > >>>>>>>>> REG_S a0, (a2)
> > >>>>>>>>>
> > >>>>>>>>> /* Initialize page tables and relocate to virtual
> > >>>>>>>>> addresses */
> > >>>>>>>>> la sp, init_thread_union + THREAD_SIZE
> > >>>>>>>>> + XIP_FIXUP_OFFSET sp
> > >>>>>>>>> #ifdef CONFIG_BUILTIN_DTB
> > >>>>>>>>> la a0, __dtb_start
> > >>>>>>>>> #else
> > >>>>>>>>> @@ -268,6 +312,7 @@ clear_bss_done:
> > >>>>>>>>> call setup_vm
> > >>>>>>>>> #ifdef CONFIG_MMU
> > >>>>>>>>> la a0, early_pg_dir
> > >>>>>>>>> + XIP_FIXUP_OFFSET a0
> > >>>>>>>>> call relocate
> > >>>>>>>>> #endif /* CONFIG_MMU */
> > >>>>>>>>>
> > >>>>>>>>> @@ -292,7 +337,9 @@ clear_bss_done:
> > >>>>>>>>>
> > >>>>>>>>> slli a3, a0, LGREG
> > >>>>>>>>> la a1, __cpu_up_stack_pointer
> > >>>>>>>>> + XIP_FIXUP_OFFSET a1
> > >>>>>>>>> la a2, __cpu_up_task_pointer
> > >>>>>>>>> + XIP_FIXUP_OFFSET a2
> > >>>>>>>>> add a1, a3, a1
> > >>>>>>>>> add a2, a3, a2
> > >>>>>>>>>
> > >>>>>>>>> diff --git a/arch/riscv/kernel/head.h b/arch/riscv/kernel/head.h
> > >>>>>>>>> index b48dda3d04f6..aabbc3ac3e48 100644
> > >>>>>>>>> --- a/arch/riscv/kernel/head.h
> > >>>>>>>>> +++ b/arch/riscv/kernel/head.h
> > >>>>>>>>> @@ -12,6 +12,9 @@ extern atomic_t hart_lottery;
> > >>>>>>>>>
> > >>>>>>>>> asmlinkage void do_page_fault(struct pt_regs *regs);
> > >>>>>>>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa);
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +asmlinkage void __init __copy_data(void);
> > >>>>>>>>> +#endif
> > >>>>>>>>>
> > >>>>>>>>> extern void *__cpu_up_stack_pointer[];
> > >>>>>>>>> extern void *__cpu_up_task_pointer[];
> > >>>>>>>>> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> > >>>>>>>>> index e85bacff1b50..a0384c72c272 100644
> > >>>>>>>>> --- a/arch/riscv/kernel/setup.c
> > >>>>>>>>> +++ b/arch/riscv/kernel/setup.c
> > >>>>>>>>> @@ -50,7 +50,11 @@ struct screen_info screen_info
> > >>>>>>>>> __section(".data") = {
> > >>>>>>>>> * This is used before the kernel initializes the BSS so it
> > >>>>>>>>> can't be in the
> > >>>>>>>>> * BSS.
> > >>>>>>>>> */
> > >>>>>>>>> -atomic_t hart_lottery __section(".sdata");
> > >>>>>>>>> +atomic_t hart_lottery __section(".sdata")
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> += ATOMIC_INIT(0xC001BEEF)
> > >>>>>>>>> +#endif
> > >>>>>>>>> +;
> > >>>>>>>>> unsigned long boot_cpu_hartid;
> > >>>>>>>>> static DEFINE_PER_CPU(struct cpu, cpu_devices);
> > >>>>>>>>>
> > >>>>>>>>> @@ -254,7 +258,7 @@ void __init setup_arch(char **cmdline_p)
> > >>>>>>>>> #if IS_ENABLED(CONFIG_BUILTIN_DTB)
> > >>>>>>>>> unflatten_and_copy_device_tree();
> > >>>>>>>>> #else
> > >>>>>>>>> - if (early_init_dt_verify(__va(dtb_early_pa)))
> > >>>>>>>>> + if (early_init_dt_verify(__va(XIP_FIXUP(dtb_early_pa))))
> > >>>>>>>>> unflatten_device_tree();
> > >>>>>>>>> else
> > >>>>>>>>> pr_err("No DTB found in kernel mappings\n");
> > >>>>>>>>> diff --git a/arch/riscv/kernel/vmlinux-xip.lds.S
> > >>>>>>>>> b/arch/riscv/kernel/vmlinux-xip.lds.S
> > >>>>>>>>> new file mode 100644
> > >>>>>>>>> index 000000000000..9f0f08c34cd3
> > >>>>>>>>> --- /dev/null
> > >>>>>>>>> +++ b/arch/riscv/kernel/vmlinux-xip.lds.S
> > >>>>>>>>> @@ -0,0 +1,132 @@
> > >>>>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
> > >>>>>>>>> +/*
> > >>>>>>>>> + * Copyright (C) 2012 Regents of the University of California
> > >>>>>>>>> + * Copyright (C) 2017 SiFive
> > >>>>>>>>> + * Copyright (C) 2020 Vitaly Wool, Konsulko AB
> > >>>>>>>>> + */
> > >>>>>>>>> +
> > >>>>>>>>> +#define LOAD_OFFSET XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
> > >>>>>>>>> +/* No __ro_after_init data in the .rodata section - which will
> > >>>>>>>>> always be ro */
> > >>>>>>>>> +#define RO_AFTER_INIT_DATA
> > >>>>>>>>> +
> > >>>>>>>>> +#include <asm/vmlinux.lds.h>
> > >>>>>>>>> +#include <asm/page.h>
> > >>>>>>>>> +#include <asm/pgtable.h>
> > >>>>>>>>> +#include <asm/cache.h>
> > >>>>>>>>> +#include <asm/thread_info.h>
> > >>>>>>>>> +
> > >>>>>>>>> +OUTPUT_ARCH(riscv)
> > >>>>>>>>> +ENTRY(_start)
> > >>>>>>>>> +
> > >>>>>>>>> +jiffies = jiffies_64;
> > >>>>>>>>> +
> > >>>>>>>>> +SECTIONS
> > >>>>>>>>> +{
> > >>>>>>>>> + /* Beginning of code and text segment */
> > >>>>>>>>> + . = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
> > >>>>>>>>> + _xiprom = .;
> > >>>>>>>>> + _start = .;
> > >>>>>>>>> + HEAD_TEXT_SECTION
> > >>>>>>>>> + INIT_TEXT_SECTION(PAGE_SIZE)
> > >>>>>>>>> + /* we have to discard exit text and such at runtime, not
> > >>>>>>>>> link time */
> > >>>>>>>>> + .exit.text :
> > >>>>>>>>> + {
> > >>>>>>>>> + EXIT_TEXT
> > >>>>>>>>> + }
> > >>>>>>>>> +
> > >>>>>>>>> + .text : {
> > >>>>>>>>> + _text = .;
> > >>>>>>>>> + _stext = .;
> > >>>>>>>>> + TEXT_TEXT
> > >>>>>>>>> + SCHED_TEXT
> > >>>>>>>>> + CPUIDLE_TEXT
> > >>>>>>>>> + LOCK_TEXT
> > >>>>>>>>> + KPROBES_TEXT
> > >>>>>>>>> + ENTRY_TEXT
> > >>>>>>>>> + IRQENTRY_TEXT
> > >>>>>>>>> + SOFTIRQENTRY_TEXT
> > >>>>>>>>> + *(.fixup)
> > >>>>>>>>> + _etext = .;
> > >>>>>>>>> + }
> > >>>>>>>>> + RO_DATA(L1_CACHE_BYTES)
> > >>>>>>>>> + .srodata : {
> > >>>>>>>>> + *(.srodata*)
> > >>>>>>>>> + }
> > >>>>>>>>> + .init.rodata : {
> > >>>>>>>>> + INIT_SETUP(16)
> > >>>>>>>>> + INIT_CALLS
> > >>>>>>>>> + CON_INITCALL
> > >>>>>>>>> + INIT_RAM_FS
> > >>>>>>>>> + }
> > >>>>>>>>> + _exiprom = .; /* End of XIP ROM area */
> > >>>>>>>>> +
> > >>>>>>>>> +
> > >>>>>>>>> +/*
> > >>>>>>>>> + * From this point, stuff is considered writable and will be
> > >>>>>>>>> copied to RAM
> > >>>>>>>>> + */
> > >>>>>>>>> + __data_loc = ALIGN(16); /* location in file */
> > >>>>>>>>> + . = PAGE_OFFSET; /* location in memory */
> > >>>>>>>>> +
> > >>>>>>>>> + _sdata = .; /* Start of data section */
> > >>>>>>>>> + _data = .;
> > >>>>>>>>> + RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
> > >>>>>>>>> + _edata = .;
> > >>>>>>>>> + __start_ro_after_init = .;
> > >>>>>>>>> + .data.ro_after_init : AT(ADDR(.data.ro_after_init) -
> > >>>>>>>>> LOAD_OFFSET) {
> > >>>>>>>>> + *(.data..ro_after_init)
> > >>>>>>>>> + }
> > >>>>>>>>> + __end_ro_after_init = .;
> > >>>>>>>>> +
> > >>>>>>>>> + . = ALIGN(PAGE_SIZE);
> > >>>>>>>>> + __init_begin = .;
> > >>>>>>>>> + .init.data : {
> > >>>>>>>>> + INIT_DATA
> > >>>>>>>>> + }
> > >>>>>>>>> + .exit.data : {
> > >>>>>>>>> + EXIT_DATA
> > >>>>>>>>> + }
> > >>>>>>>>> + . = ALIGN(8);
> > >>>>>>>>> + __soc_early_init_table : {
> > >>>>>>>>> + __soc_early_init_table_start = .;
> > >>>>>>>>> + KEEP(*(__soc_early_init_table))
> > >>>>>>>>> + __soc_early_init_table_end = .;
> > >>>>>>>>> + }
> > >>>>>>>>> + __soc_builtin_dtb_table : {
> > >>>>>>>>> + __soc_builtin_dtb_table_start = .;
> > >>>>>>>>> + KEEP(*(__soc_builtin_dtb_table))
> > >>>>>>>>> + __soc_builtin_dtb_table_end = .;
> > >>>>>>>>> + }
> > >>>>>>>>> + PERCPU_SECTION(L1_CACHE_BYTES)
> > >>>>>>>>> +
> > >>>>>>>>> + . = ALIGN(PAGE_SIZE);
> > >>>>>>>>> + __init_end = .;
> > >>>>>>>>> +
> > >>>>>>>>> + .sdata : {
> > >>>>>>>>> + __global_pointer$ = . + 0x800;
> > >>>>>>>>> + *(.sdata*)
> > >>>>>>>>> + *(.sbss*)
> > >>>>>>>>> + }
> > >>>>>>>>> +
> > >>>>>>>>> + BSS_SECTION(PAGE_SIZE, PAGE_SIZE, 0)
> > >>>>>>>>> + EXCEPTION_TABLE(0x10)
> > >>>>>>>>> +
> > >>>>>>>>> + .rel.dyn : AT(ADDR(.rel.dyn) - LOAD_OFFSET) {
> > >>>>>>>>> + *(.rel.dyn*)
> > >>>>>>>>> + }
> > >>>>>>>>> +
> > >>>>>>>>> + /*
> > >>>>>>>>> + * End of copied data. We need a dummy section to get its
> > >>>>>>>>> LMA.
> > >>>>>>>>> + * Also located before final ALIGN() as trailing padding is
> > >>>>>>>>> not stored
> > >>>>>>>>> + * in the resulting binary file and useless to copy.
> > >>>>>>>>> + */
> > >>>>>>>>> + .data.endmark : AT(ADDR(.data.endmark) - LOAD_OFFSET) { }
> > >>>>>>>>> + _edata_loc = LOADADDR(.data.endmark);
> > >>>>>>>>> +
> > >>>>>>>>> + . = ALIGN(PAGE_SIZE);
> > >>>>>>>>> + _end = .;
> > >>>>>>>>> +
> > >>>>>>>>> + STABS_DEBUG
> > >>>>>>>>> + DWARF_DEBUG
> > >>>>>>>>> +
> > >>>>>>>>> + DISCARDS
> > >>>>>>>>> +}
> > >>>>>>>>> diff --git a/arch/riscv/kernel/vmlinux.lds.S
> > >>>>>>>>> b/arch/riscv/kernel/vmlinux.lds.S
> > >>>>>>>>> index de03cb22d0e9..6745ec325930 100644
> > >>>>>>>>> --- a/arch/riscv/kernel/vmlinux.lds.S
> > >>>>>>>>> +++ b/arch/riscv/kernel/vmlinux.lds.S
> > >>>>>>>>> @@ -4,7 +4,12 @@
> > >>>>>>>>> * Copyright (C) 2017 SiFive
> > >>>>>>>>> */
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +#include "vmlinux-xip.lds.S"
> > >>>>>>>>> +#else
> > >>>>>>>>> +
> > >>>>>>>>> #define LOAD_OFFSET PAGE_OFFSET
> > >>>>>>>>> +
> > >>>>>>>>> #include <asm/vmlinux.lds.h>
> > >>>>>>>>> #include <asm/page.h>
> > >>>>>>>>> #include <asm/cache.h>
> > >>>>>>>>> @@ -132,3 +137,4 @@ SECTIONS
> > >>>>>>>>>
> > >>>>>>>>> DISCARDS
> > >>>>>>>>> }
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > >>>>>>>>> index 7f5036fbee8c..efe649d41f95 100644
> > >>>>>>>>> --- a/arch/riscv/mm/init.c
> > >>>>>>>>> +++ b/arch/riscv/mm/init.c
> > >>>>>>>>> @@ -31,8 +31,8 @@ EXPORT_SYMBOL(empty_zero_page);
> > >>>>>>>>>
> > >>>>>>>>> extern char _start[];
> > >>>>>>>>> #define DTB_EARLY_BASE_VA PGDIR_SIZE
> > >>>>>>>>> -void *dtb_early_va __initdata;
> > >>>>>>>>> -uintptr_t dtb_early_pa __initdata;
> > >>>>>>>>> +void *_dtb_early_va __initdata;
> > >>>>>>>>> +uintptr_t _dtb_early_pa __initdata;
> > >>>>>>>>>
> > >>>>>>>>> struct pt_alloc_ops {
> > >>>>>>>>> pte_t *(*get_pte_virt)(phys_addr_t pa);
> > >>>>>>>>> @@ -88,6 +88,10 @@ static void print_vm_layout(void)
> > >>>>>>>>> (unsigned long)VMALLOC_END);
> > >>>>>>>>> print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
> > >>>>>>>>> (unsigned long)high_memory);
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + print_mlm("xip", (unsigned long)XIP_VIRT_ADDR_START,
> > >>>>>>>>> + (unsigned long)XIP_VIRT_ADDR_START + SZ_16M);
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> }
> > >>>>>>>>> #else
> > >>>>>>>>> static void print_vm_layout(void) { }
> > >>>>>>>>> @@ -113,6 +117,10 @@ void __init setup_bootmem(void)
> > >>>>>>>>> phys_addr_t dram_end = memblock_end_of_DRAM();
> > >>>>>>>>> phys_addr_t max_mapped_addr = __pa(~(ulong)0);
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + vmlinux_start = __pa_symbol(&_sdata);
> > >>>>>>>>> +#endif
> > >>>>>>>>> +
> > >>>>>>>>> /* The maximal physical memory size is -PAGE_OFFSET. */
> > >>>>>>>>> memblock_enforce_memory_limit(-PAGE_OFFSET);
> > >>>>>>>>>
> > >>>>>>>>> @@ -149,11 +157,27 @@ void __init setup_bootmem(void)
> > >>>>>>>>> memblock_allow_resize();
> > >>>>>>>>> }
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +
> > >>>>>>>>> +extern char _xiprom[], _exiprom[];
> > >>>>>>>>> +extern char _sdata[], _edata[];
> > >>>>>>>>> +
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +
> > >>>>>>>>> #ifdef CONFIG_MMU
> > >>>>>>>>> -static struct pt_alloc_ops pt_ops;
> > >>>>>>>>> +static struct pt_alloc_ops _pt_ops;
> > >>>>>>>>> +
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +#define pt_ops (*(struct pt_alloc_ops *)XIP_FIXUP(&_pt_ops))
> > >>>>>>>>> +#else
> > >>>>>>>>> +#define pt_ops _pt_ops
> > >>>>>>>>> +#endif
> > >>>>>>>>>
> > >>>>>>>>> unsigned long va_pa_offset;
> > >>>>>>>>> EXPORT_SYMBOL(va_pa_offset);
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +#define va_pa_offset (*((unsigned long
> > >>>>>>>>> *)XIP_FIXUP(&va_pa_offset)))
> > >>>>>>>>> +#endif
> > >>>>>>>>> unsigned long pfn_base;
> > >>>>>>>>> EXPORT_SYMBOL(pfn_base);
> > >>>>>>>>>
> > >>>>>>>>> @@ -163,6 +187,12 @@ pte_t fixmap_pte[PTRS_PER_PTE]
> > >>>>>>>>> __page_aligned_bss;
> > >>>>>>>>>
> > >>>>>>>>> pgd_t early_pg_dir[PTRS_PER_PGD] __initdata
> > >>>>>>>>> __aligned(PAGE_SIZE);
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +#define trampoline_pg_dir ((pgd_t
> > >>>>>>>>> *)XIP_FIXUP(trampoline_pg_dir))
> > >>>>>>>>> +#define fixmap_pte ((pte_t *)XIP_FIXUP(fixmap_pte))
> > >>>>>>>>> +#define early_pg_dir ((pgd_t *)XIP_FIXUP(early_pg_dir))
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +
> > >>>>>>>>> void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
> > >>>>>>>>> pgprot_t prot)
> > >>>>>>>>> {
> > >>>>>>>>> unsigned long addr = __fix_to_virt(idx);
> > >>>>>>>>> @@ -238,6 +268,15 @@ pmd_t fixmap_pmd[PTRS_PER_PMD]
> > >>>>>>>>> __page_aligned_bss;
> > >>>>>>>>> pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
> > >>>>>>>>> pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata
> > >>>>>>>>> __aligned(PAGE_SIZE);
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +pmd_t xip_pmd[PTRS_PER_PMD] __page_aligned_bss;
> > >>>>>>>>> +
> > >>>>>>>>> +#define trampoline_pmd ((pmd_t *)XIP_FIXUP(trampoline_pmd))
> > >>>>>>>>> +#define fixmap_pmd ((pmd_t *)XIP_FIXUP(fixmap_pmd))
> > >>>>>>>>> +#define xip_pmd ((pmd_t *)XIP_FIXUP(xip_pmd))
> > >>>>>>>>> +#define early_pmd ((pmd_t *)XIP_FIXUP(early_pmd))
> > >>>>>>>>> +#endif /* CONFIG_XIP_KERNEL */
> > >>>>>>>>> +
> > >>>>>>>>> static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
> > >>>>>>>>> {
> > >>>>>>>>> /* Before MMU is enabled */
> > >>>>>>>>> @@ -354,6 +393,19 @@ static uintptr_t __init
> > >>>>>>>>> best_map_size(phys_addr_t base, phys_addr_t size)
> > >>>>>>>>> return PMD_SIZE;
> > >>>>>>>>> }
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> +/* called from head.S with MMU off */
> > >>>>>>>>> +asmlinkage void __init __copy_data(void)
> > >>>>>>>>> +{
> > >>>>>>>>> + void *from = (void *)(&_sdata);
> > >>>>>>>>> + void *end = (void *)(&_end);
> > >>>>>>>>> + void *to = (void *)CONFIG_PHYS_RAM_BASE;
> > >>>>>>>>> + size_t sz = (size_t)(end - from);
> > >>>>>>>>> +
> > >>>>>>>>> + memcpy(to, from, sz);
> > >>>>>>>>> +}
> > >>>>>>>>> +#endif
> > >>>>>>>>> +
> > >>>>>>>>> /*
> > >>>>>>>>> * setup_vm() is called from head.S with MMU-off.
> > >>>>>>>>> *
> > >>>>>>>>> @@ -374,7 +426,8 @@ static uintptr_t __init
> > >>>>>>>>> best_map_size(phys_addr_t base, phys_addr_t size)
> > >>>>>>>>>
> > >>>>>>>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa)
> > >>>>>>>>> {
> > >>>>>>>>> - uintptr_t va, pa, end_va;
> > >>>>>>>>> + uintptr_t va, end_va;
> > >>>>>>>>> + uintptr_t __maybe_unused pa;
> > >>>>>>>>> uintptr_t load_pa = (uintptr_t)(&_start);
> > >>>>>>>>> uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
> > >>>>>>>>> uintptr_t map_size;
> > >>>>>>>>> @@ -382,6 +435,13 @@ asmlinkage void __init setup_vm(uintptr_t
> > >>>>>>>>> dtb_pa)
> > >>>>>>>>> pmd_t fix_bmap_spmd, fix_bmap_epmd;
> > >>>>>>>>> #endif
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + uintptr_t xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
> > >>>>>>>>> + uintptr_t xiprom_sz = (uintptr_t)(&_exiprom) -
> > >>>>>>>>> (uintptr_t)(&_xiprom);
> > >>>>>>>>> +
> > >>>>>>>>> + load_pa = (uintptr_t)CONFIG_PHYS_RAM_BASE;
> > >>>>>>>>> + load_sz = (uintptr_t)(&_end) - (uintptr_t)(&_sdata);
> > >>>>>>>>> +#endif
> > >>>>>>>>> va_pa_offset = PAGE_OFFSET - load_pa;
> > >>>>>>
> > >>>>>> I should have seen this before, I was too focused on having a XIP
> > >>>>>> kernel
> > >>>>>> boot. I already moved the kernel mapping in the vmalloc zone: the
> > >>>>>> virtual to physical translations need to be handled differently
> > >>>>>> now that
> > >>>>>> the kernel mapping does not lie into linear mapping anymore, we can't
> > >>>>>> use va_pa_offset defined above for both mappings.
> > >>>>>>
> > >>>>>> I was rebasing my patchset on the XIP patch but I believe that
> > >>>>>> doing the
> > >>>>>> other way around would greatly simplify the XIP patch as the kernel
> > >>>>>> mapping would already be moved outside the linear mapping, there
> > >>>>>> would
> > >>>>>> be no need to reserve a zone in vmalloc anymore (that simplifies
> > >>>>>> pgtable.h quite a lot). And the XIP kernel mapping could be
> > >>>>>> implemented
> > >>>>>> in a new create_kernel_page_table (that would also simplify
> > >>>>>> mm/init.c).
> > >>>>>>
> > >>>>>> I can help to do that but I don't think we should merge this patch
> > >>>>>> as is
> > >>>>>> now.
> > >>>>>
> > >>>>> I think that's the right way to go for now: it's a lot harder to test
> > >>>>> the XIP stuff, as it requires a bunch of harness changes. So let's
> > >>>>> take the page table refactoring in now and rebase this stuff on top of
> > >>>>> it. There's really no way to do both without making more work for
> > >>>>> someone, it's just a headache on timing.
> > >>>>>
> > >>>>> Alex: if you want to sign up to spend some time there that'd be great,
> > >>>>> otherwise I will.
> > >>>>
> > >>>> I can take care of that, no problem.
> > >>>
> > >>> Vitaly, can you try the branch int/alex/riscv_xip_kernel_rebase_v1 at
> > >>> https://github.com/AlexGhiti/riscv-linux ? This boots fine using my
> > >>> setup.
> > >>>
> > >>> I removed most of the pgtable.h stuff, the XIP kernel is now mapped like
> > >>> any other kernel at the end of the address space, not in the vmalloc
> > >>> zone as you proposed. And I fixed a few thigns along the way (pfn_base,
> > >>> pfn_valid, copy_data and other stuff).
> > >>>
> > >>> Any comment is welcome !
> > >>
> > >> thanks for your efforts!
> > >>
> > >> I've just built your version. The build went well, but the image
> > >> doesn't seem to boot for me.
> > >
> > > Too bad. Can you give me your config please ?
> > >
> >
> > Apparently, as you can see below, your config works for me, at least it
> > reaches userspace. Do you have traces or more info about what is wrong ?
>
> Console output is just the same but it stops after the following line:
> [ 0.003208] Console: colour dummy device 80x25
>
> I did some very simplistic debugging bisecting start_kernel()
> execution and I could see that setup_per_cpu_pageset() was reached
> while calibrate_delay() was not.
>
> How (and whether) this might be related to XIP I don't know :)

A short update: the system would hang in sched_clock_init() if run
with 'go 21000000' command.
If I use 'booti' command it passes and goes further all the way to
mounting the userspace

So the problem is rather SMP related than XIP related.

Best regards,
Vitaly

> > Thanks!
> >
> > [ 0.000000] Linux version 5.12.0-rc2 (alex@debian)
> > (riscv64-buildroot-linux-gnu-gcc.br_real (Buildroot 2020.11.2) 9.3.0,
> > GNU ld (GNU Binutils) 2.34) #322 SMP Sat Apr 3 05:50:18 EDT 2021
> > [ 0.000000] Machine model: Microchip PolarFire-SoC Icicle Kit
> > [ 0.000000] earlycon: sbi0 at I/O port 0x0 (options '')
> > [ 0.000000] printk: bootconsole [sbi0] enabled
> > [ 0.000000] Zone ranges:
> > [ 0.000000] DMA32 [mem 0x0000000080000000-0x00000000bfffffff]
> > [ 0.000000] Normal empty
> > [ 0.000000] Movable zone start for each node
> > [ 0.000000] Early memory node ranges
> > [ 0.000000] node 0: [mem 0x0000000080000000-0x00000000bfffffff]
> > [ 0.000000] Initmem setup node 0 [mem
> > 0x0000000080000000-0x00000000bfffffff]
> > [ 0.000000] On node 0 totalpages: 262144
> > [ 0.000000] DMA32 zone: 3584 pages used for memmap
> > [ 0.000000] DMA32 zone: 0 pages reserved
> > [ 0.000000] DMA32 zone: 262144 pages, LIFO batch:63
> > [ 0.000000] SBI specification v0.2 detected
> > [ 0.000000] SBI implementation ID=0x1 Version=0x6
> > [ 0.000000] SBI v0.2 TIME extension detected
> > [ 0.000000] SBI v0.2 IPI extension detected
> > [ 0.000000] SBI v0.2 RFENCE extension detected
> > [ 0.000000] software IO TLB: mapped [mem
> > 0x00000000b9e00000-0x00000000bde00000] (64MB)
> > [ 0.000000] CPU with hartid=0 is not available
> > [ 0.000000] CPU with hartid=0 is not available
> > [ 0.000000] riscv: ISA extensions acdfim
> > [ 0.000000] riscv: ELF capabilities acdfim
> > [ 0.000000] percpu: Embedded 17 pages/cpu s29856 r8192 d31584 u69632
> > [ 0.000000] pcpu-alloc: s29856 r8192 d31584 u69632 alloc=17*4096
> > [ 0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
> > [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 258560
> > [ 0.000000] Kernel command line: earlyprintk debug earlycon=sbi
> > console=ttyS0,115200n8 root=/dev/ram0 init=/sbin/init
> > [ 0.000000] Dentry cache hash table entries: 131072 (order: 8,
> > 1048576 bytes, linear)
> > [ 0.000000] Inode-cache hash table entries: 65536 (order: 7, 524288
> > bytes, linear)
> > [ 0.000000] Sorting __ex_table...
> > [ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
> > [ 0.000000] Memory: 947732K/1048576K available (2999K kernel code,
> > 692K rwdata, 953K rodata, 205K init, 247K bss, 100844K reserved, 0K
> > cma-reserved)
> > [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
> > [ 0.000000] rcu: Hierarchical RCU implementation.
> > [ 0.000000] rcu: RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
> > [ 0.000000] rcu: RCU debug extended QS entry/exit.
> > [ 0.000000] Tracing variant of Tasks RCU enabled.
> > [ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay
> > is 25 jiffies.
> > [ 0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
> > [ 0.000000] NR_IRQS: 64, nr_irqs: 64, preallocated irqs: 0
> > [ 0.000000] CPU with hartid=0 is not available
> > [ 0.000000] riscv-intc: unable to find hart id for
> > /cpus/cpu@0/interrupt-controller
> > [ 0.000000] riscv-intc: 64 local interrupts mapped
> > [ 0.000000] plic: interrupt-controller@c000000: mapped 186 interrupts
> > with 4 handlers for 9 contexts.
> > [ 0.000000] random: get_random_bytes called from
> > start_kernel+0x2fe/0x49c with crng_init=0
> > [ 0.000000] riscv_timer_init_dt: Registering clocksource cpuid [0]
> > hartid [1]
> > [ 0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff
> > max_cycles: 0x1d854df40, max_idle_ns: 3526361616960 ns
> > [ 0.000146] sched_clock: 64 bits at 1000kHz, resolution 1000ns, wraps
> > every 2199023255500ns
> > [ 0.006056] Console: colour dummy device 80x25
> > [ 0.015242] Calibrating delay loop (skipped), value calculated using
> > timer frequency.. 2.00 BogoMIPS (lpj=4000)
> > [ 0.017130] pid_max: default: 32768 minimum: 301
> > [ 0.020115] Mount-cache hash table entries: 2048 (order: 2, 16384
> > bytes, linear)
> > [ 0.021097] Mountpoint-cache hash table entries: 2048 (order: 2,
> > 16384 bytes, linear)
> > [ 0.078755] ASID allocator using 16 bits (65536 entries)
> > [ 0.083669] rcu: Hierarchical SRCU implementation.
> > [ 0.093304] smp: Bringing up secondary CPUs ...
> > [ 1.149900] CPU1: failed to come online
> > [ 2.204183] CPU2: failed to come online
> > [ 3.256211] CPU3: failed to come online
> > [ 3.257043] smp: Brought up 1 node, 1 CPU
> > [ 3.269554] devtmpfs: initialized
> > [ 3.282015] clocksource: jiffies: mask: 0xffffffff max_cycles:
> > 0xffffffff, max_idle_ns: 7645041785100000 ns
> > [ 3.283484] futex hash table entries: 1024 (order: 4, 65536 bytes,
> > linear)
> > [ 3.381718] SCSI subsystem initialized
> > [ 3.385115] clocksource: Switched to clocksource riscv_clocksource
> > [ 3.602198] workingset: timestamp_bits=62 max_order=18 bucket_order=0
> > [ 3.624182] Block layer SCSI generic (bsg) driver version 0.4 loaded
> > (major 253)
> > [ 3.625988] io scheduler mq-deadline registered
> > [ 3.626725] io scheduler kyber registered
> > [ 3.629047] start plist test
> > [ 3.641420] end plist test
> > [ 3.717639] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
> > [ 3.752315] brd: module loaded
> > [ 3.790207] loop: module loaded
> > [ 3.793943] mousedev: PS/2 mouse device common for all mice
> > [ 3.810511] Warning: unable to open an initial console.
> > [ 3.811923] Freeing unused kernel memory: 88K
> > [ 3.812558] This architecture does not have kernel memory protection.
> > [ 3.814280] Run /init as init process
> > [ 3.814808] with arguments:
> > [ 3.815227] /init
> > [ 3.815539] with environment:
> > [ 3.815924] HOME=/
> > [ 3.816250] TERM=linux
> > [ 4.398678] random: dd: uninitialized urandom read (512 bytes read)
> >
> >
> > > Thanks,
> > >
> > > Alex
> > >
> > >> I'll take a look at the code later today.
> > >>
> > >> Best regards,
> > >> Vitaly
> > >>
> > >>> Thanks,
> > >>>
> > >>> Alex
> > >>>
> > >>>>
> > >>>>> Either way, can you point me (either just indicate the old version is
> > >>>>> OK or send a new one) to what you want me to look at WRT the page
> > >>>>> table code? IIRC it looked pretty much fine, but I'll take another
> > >>>>> look ASAP so we can avoid serializing everything.
> > >>>>
> > >>>> The v3 is fine for me:
> > >>>> https://patchwork.kernel.org/project/linux-riscv/list/?series=447699
> > >>>>
> > >>>>>
> > >>>>>>
> > >>>>>> Alex
> > >>>>>>
> > >>>>>>>>> pfn_base = PFN_DOWN(load_pa);
> > >>>>>>>>>
> > >>>>>>>>> @@ -420,6 +480,21 @@ asmlinkage void __init setup_vm(uintptr_t
> > >>>>>>>>> dtb_pa)
> > >>>>>>>>> load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
> > >>>>>>>>> #endif
> > >>>>>>>>>
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + create_pgd_mapping(trampoline_pg_dir, XIP_VIRT_ADDR_START,
> > >>>>>>>>> + (uintptr_t)xip_pmd, PGDIR_SIZE,
> > >>>>>>>>> PAGE_TABLE);
> > >>>>>>>>> + for (va = XIP_VIRT_ADDR_START;
> > >>>>>>>>> + va < XIP_VIRT_ADDR_START + xiprom_sz;
> > >>>>>>>>> + va += PMD_SIZE) {
> > >>>>>>>>> + create_pmd_mapping(xip_pmd, va,
> > >>>>>>>>> + xiprom + (va -
> > >>>>>>>>> XIP_VIRT_ADDR_START),
> > >>>>>>>>> + PMD_SIZE, PAGE_KERNEL_EXEC);
> > >>>>>>>>> + }
> > >>>>>>>>> +
> > >>>>>>>>> + create_pgd_mapping(early_pg_dir, XIP_VIRT_ADDR_START,
> > >>>>>>>>> + (uintptr_t)xip_pmd, PGDIR_SIZE,
> > >>>>>>>>> PAGE_TABLE);
> > >>>>>>>>> +#endif
> > >>>>>>>>> +
> > >>>>>>>>> /*
> > >>>>>>>>> * Setup early PGD covering entire kernel which will
> > >>>>>>>>> allows
> > >>>>>>>>> * us to reach paging_init(). We map all memory banks
> > >>>>>>>>> later
> > >>>>>>>>> @@ -444,7 +519,7 @@ asmlinkage void __init setup_vm(uintptr_t
> > >>>>>>>>> dtb_pa)
> > >>>>>>>>> pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
> > >>>>>>>>> dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa &
> > >>>>>>>>> (PMD_SIZE - 1));
> > >>>>>>>>> #else /* CONFIG_BUILTIN_DTB */
> > >>>>>>>>> - dtb_early_va = __va(dtb_pa);
> > >>>>>>>>> + dtb_early_va = __va(XIP_FIXUP(dtb_pa));
> > >>>>>>>>> #endif /* CONFIG_BUILTIN_DTB */
> > >>>>>>>>> #else
> > >>>>>>>>> #ifndef CONFIG_BUILTIN_DTB
> > >>>>>>>>> @@ -456,7 +531,7 @@ asmlinkage void __init setup_vm(uintptr_t
> > >>>>>>>>> dtb_pa)
> > >>>>>>>>> pa + PGDIR_SIZE, PGDIR_SIZE,
> > >>>>>>>>> PAGE_KERNEL);
> > >>>>>>>>> dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa &
> > >>>>>>>>> (PGDIR_SIZE - 1));
> > >>>>>>>>> #else /* CONFIG_BUILTIN_DTB */
> > >>>>>>>>> - dtb_early_va = __va(dtb_pa);
> > >>>>>>>>> + dtb_early_va = __va(XIP_FIXUP(dtb_pa));
> > >>>>>>>>> #endif /* CONFIG_BUILTIN_DTB */
> > >>>>>>>>> #endif
> > >>>>>>>>> dtb_early_pa = dtb_pa;
> > >>>>>>>>> @@ -497,6 +572,9 @@ static void __init setup_vm_final(void)
> > >>>>>>>>> uintptr_t va, map_size;
> > >>>>>>>>> phys_addr_t pa, start, end;
> > >>>>>>>>> u64 i;
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + uintptr_t xiprom_sz = (uintptr_t)(&_exiprom) -
> > >>>>>>>>> (uintptr_t)(&_xiprom);
> > >>>>>>>>> +#endif
> > >>>>>>>>>
> > >>>>>>>>> /**
> > >>>>>>>>> * MMU is enabled at this point. But page table setup is
> > >>>>>>>>> not complete yet.
> > >>>>>>>>> @@ -528,6 +606,16 @@ static void __init setup_vm_final(void)
> > >>>>>>>>> map_size,
> > >>>>>>>>> PAGE_KERNEL_EXEC);
> > >>>>>>>>> }
> > >>>>>>>>> }
> > >>>>>>>>> +#ifdef CONFIG_XIP_KERNEL
> > >>>>>>>>> + map_size = best_map_size(CONFIG_XIP_PHYS_ADDR, xiprom_sz);
> > >>>>>>>>> + for (va = XIP_VIRT_ADDR_START;
> > >>>>>>>>> + va < XIP_VIRT_ADDR_START + xiprom_sz;
> > >>>>>>>>> + va += map_size)
> > >>>>>>>>> + create_pgd_mapping(swapper_pg_dir, va,
> > >>>>>>>>> + CONFIG_XIP_PHYS_ADDR + (va -
> > >>>>>>>>> XIP_VIRT_ADDR_START),
> > >>>>>>>>> + map_size, PAGE_KERNEL_EXEC);
> > >>>>>>>>> +
> > >>>>>>>>> +#endif
> > >>>>>>>>>
> > >>>>>>>>> /* Clear fixmap PTE and PMD mappings */
> > >>>>>>>>> clear_fixmap(FIX_PTE);
> > >>>>>>>
> > >>>>>>> _______________________________________________
> > >>>>>>> linux-riscv mailing list
> > >>>>>>> linux-riscv@xxxxxxxxxxxxxxxxxxx
> > >>>>>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> > >>>>>>>
> > >>>>>
> > >>>>> _______________________________________________
> > >>>>> linux-riscv mailing list
> > >>>>> linux-riscv@xxxxxxxxxxxxxxxxxxx
> > >>>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> > >>>>
> > >>>> _______________________________________________
> > >>>> linux-riscv mailing list
> > >>>> linux-riscv@xxxxxxxxxxxxxxxxxxx
> > >>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> > >>
> > >> _______________________________________________
> > >> linux-riscv mailing list
> > >> linux-riscv@xxxxxxxxxxxxxxxxxxx
> > >> http://lists.infradead.org/mailman/listinfo/linux-riscv
> > >>

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