Yash Shah e0d17c842c RISC-V: Don't allow write+exec only page mapping request in mmap ... As per the table 4.4 of version "20190608-Priv-MSU-Ratified" of the RISC-V instruction set manual[0], the PTE permission bit combination of "write+exec only" is reserved for future use. Hence, don't allow such mapping request in mmap call. An issue is been reported by David Abdurachmanov, that while running stress-ng with "sysbadaddr" argument, RCU stalls are observed on RISC-V specific kernel. This issue arises when the stress-sysbadaddr request for pages with "write+exec only" permission bits and then passes the address obtain from this mmap call to various system call. For the riscv kernel, the mmap call should fail for this particular combination of permission bits since it's not valid. [0]: http://dabbelt.com/~palmer/keep/riscv-isa-manual/riscv-privileged-20190608-1.pdf Signed-off-by: Yash Shah <yash.shah@sifive.com> Reported-by: David Abdurachmanov <david.abdurachmanov@gmail.com> [Palmer: Refer to the latest ISA specification at the only link I could find, and update the terminology.] Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>		2020-06-18 17:28:53 -07:00
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boot	riscv: K210: Add a built-in device tree	2020-05-18 11:38:06 -07:00
configs	riscv: K210: Update defconfig	2020-05-18 11:38:07 -07:00
include	riscv/atomic: Fix sign extension for RV64I	2020-06-12 12:07:58 -07:00
kernel	RISC-V: Don't allow write+exec only page mapping request in mmap	2020-06-18 17:28:53 -07:00
lib	RISC-V Patches for the 5.7 Merge Window, Part 1	2020-04-09 10:51:30 -07:00
mm	RISC-V Patches for the 5.8 Merge Window, Part 2	2020-06-11 12:55:20 -07:00
net	bpf, riscv: Optimize BPF_JSET BPF_K using andi on RV64	2020-05-06 09:48:15 +02:00
Kbuild	riscv: Allow device trees to be built into the kernel	2020-05-18 11:38:05 -07:00
Kconfig	riscv: use vDSO common flow to reduce the latency of the time-related functions	2020-06-10 19:47:16 -07:00
Kconfig.debug	RISC-V: Remove EARLY_PRINTK support	2018-12-17 10:23:46 -08:00
Kconfig.socs	riscv: K210: Add a built-in device tree	2020-05-18 11:38:06 -07:00
Makefile	RISC-V Patches for the 5.7 Merge Window, Part 1	2020-04-09 10:51:30 -07:00