Re: [PATCH v8 0/2] Map the kernel with correct permissions the first time

[Alex Ghiti]

Le 1/07/2021 à 07:37, Palmer Dabbelt a écrit :
> On Thu, 24 Jun 2021 05:00:39 PDT (-0700), alex@xxxxxxxx wrote:
> > The kernel permissions are fixed after the kernel page table is created:
> > avoid that by mapping the kernel 'correctly' the first time.
> >
> > Patch 1 introduces a new helper to set kernel mapping permissions while
> > avoiding all the casts when using set_memory_* API.
> >
> > Patch 2  is the bulk of this work and deals with mapping the kernel with
> > the right permissions.
> >
> > Changes in v8:
> > * Move set_kernel_memory inline function into set_memory.h header as 
> > suggested
> >   by Jisheng
> > * Make set_kernel_memory arguments name consistent
> >
> > Changes in v7:
> > * Split long lines and reintroduce parameters names of set_kernel_memory
> >   callback, as suggested by Christoph
> > * Make set_kernel_memory __always_inline as suggested by Christoph
> > * Change 64b spelling into 64-bit, as suggested by Christoph
> >
> > Changes in v6:
> > * load_sz was placed in init section but is now used in kernel address
> >   conversions macros, so remove this attribute.
> >
> > Changes in v5:
> > * Remove non-relevant commits to this patchset that raised issues
> > * Make load_sz non-static as it is used in kernel address conversions
> >   macros
> > * Rebased on top for-next
> >
> > Changes in v4:
> > * Add patch 1 as noted by Jisheng
> > * Changes patch 2 title as suggested by Anup
> > * Add Reviewed-by from Anup
> >
> > Changes in v3:
> > * Add a patch that factorizes kernel address conversions
> > * Add a helper called set_kernel_memory in its own patch, as suggested by
> >   Christoph
> > * Prefer IS_ENABLED over #ifdef, as suggested by Christoph
> > * Split overly long lines, as suggested by Christoph
> > * Simplify kernel mapping by mapping ALL text as readonly and taking 
> > advantage
> >   of already present code that enables write for init text before
> >   free_initmem_default.
> >
> > Changes in v2:
> > * Rebased on top of for-next (and "riscv: mm: fix build errors caused by
> >   mk_pmd()")
> > * Get rid of protect_kernel_linear_mapping_text_rodata as suggested by
> >   Jisheng
> > * Improve code in general compared to previous RFC
> >
> > Alexandre Ghiti (2):
> >   riscv: Introduce set_kernel_memory helper
> >   riscv: Map the kernel with correct permissions the first time
> >
> >  arch/riscv/include/asm/page.h       |  13 +++-
> >  arch/riscv/include/asm/sections.h   |  17 +++++
> >  arch/riscv/include/asm/set_memory.h |  24 ++++--
> >  arch/riscv/kernel/setup.c           |  12 +--
> >  arch/riscv/mm/init.c                | 112 ++++++++++++----------------
> >  5 files changed, 97 insertions(+), 81 deletions(-)
>
> I had what looks to be two earlier versions of these patches on 
> for-next.  I've fixed that up, but there were some merge conflicts. Let 
> me know if there were any issues, but it's really getting too late in 
> the cycle to be rebasing so I'd prefer just a fixup.

The first 2 patches:

riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED
riscv: Simplify xip and !xip kernel address conversion macros

should *not* be merged as they assume the DRAM physical base address is 
0x8000_0000 for *all* rv64 chips. I have another patchset coming to 
replace those 2 patches.

Alex

> Thanks!
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@xxxxxxxxxxxxxxxxxxx
> http://lists.infradead.org/mailman/listinfo/linux-riscv