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path: root/arch/riscv/mm/physaddr.c
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2021-04-26riscv: Move kernel mapping outside of linear mappingAlexandre Ghiti
This is a preparatory patch for relocatable kernel and sv48 support. The kernel used to be linked at PAGE_OFFSET address therefore we could use the linear mapping for the kernel mapping. But the relocated kernel base address will be different from PAGE_OFFSET and since in the linear mapping, two different virtual addresses cannot point to the same physical address, the kernel mapping needs to lie outside the linear mapping so that we don't have to copy it at the same physical offset. The kernel mapping is moved to the last 2GB of the address space, BPF is now always after the kernel and modules use the 2GB memory range right before the kernel, so BPF and modules regions do not overlap. KASLR implementation will simply have to move the kernel in the last 2GB range and just take care of leaving enough space for BPF. In addition, by moving the kernel to the end of the address space, both sv39 and sv48 kernels will be exactly the same without needing to be relocated at runtime. Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> [Palmer: Squash the STRICT_RWX fix, and a !MMU fix] Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-01-23riscv: mm: add support for CONFIG_DEBUG_VIRTUALZong Li
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>