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2019-10-03lib: Provide a platform hook to implement vendor specific SBI extensions.Atish Patra
SBI v0.2 specification allows vendor extensions and it should be implemented in a independent of the core sbi library. Introduce a single platform callback that will let platforms handle all vendor extensions in platform specific code if they want. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-10-03lib: Implement SBI v0.2Atish Patra
SBI v0.2 introduces a base specification which is mandatory to implement for any SBI implementations that is not legacy. Add support for the base extension. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-10-03lib: Remove redundant variable assignmentAtish Patra
An ecall handler should only return error if valid SBI function fails. Otherwise, it should succeed with appropriate error in a0. Get rid of unnecessary setting of the temporary return variable to zero for the cases where errors are not expected. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-10-03lib: Rename existing SBI implementation as 0.1.Atish Patra
Current SBI implementation is now considered as version 0.1 and will be removed/replaced with newer extension/functions in future. Rename the existing implementations accordingly to be in sync with the specification. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Anup Patel <[email protected]> Reviewed-by: Zong Li <[email protected]>
2019-10-02lib: Fix coldboot race condition observed on emulators/simulatorsAnup Patel
If we are running on RISC-V emulator/simulator with large number of HARTs where each HART is a regular thread under UNIX host then it is possible that some of the secondary HARTs don't get chance to run and sbi_hart_wake_coldboot_harts() is called before secondary HARTs call sbi_hart_wait_for_coldboot(). In this situation, some of the secondary HARTs will never come-out of coldboot wait loop. To tackle this, we introduce a global flag coldboot_done which will be protected by coldboot lock and it will be set by primary HART from sbi_hart_wake_coldboot_harts() before waking-up secondary HARTs. We also re-arrange acquire/release of coldboot lock to reduce further chances of race-condition. Signed-off-by: Anup Patel <[email protected]> Reviewed-by: Atish Patra <[email protected]> Reviewed-by: Zong Li <[email protected]> Reviewed-by: Nylon Chen<[email protected]>
2019-09-30lib: Emulate HTIMEDELTA CSR for platforms not having TIME CSRAnup Patel
For platforms not having TIME CSR, we trap-n-emulate TIME CSR read/write in OpenSBI. Same rationale applies to HTIMEDELTA CSR as well so we trap-n-emulate HTIMEDELTA CSR for platforms not having TIME CSR. Signed-off-by: Anup Patel <[email protected]>
2019-09-30include: Extend get_insn() to read instruction from VS/VU modeAnup Patel
Current implementation of get_insn() is not suitable for reading instruction from VS/VU mode because we have to set SSTATUS_MXR bit in VSSTATUS CSR for reading instruction from VS/VU mode. This patch extends get_insn() to read instruction from VS/VU mode. Signed-off-by: Anup Patel <[email protected]> Signed-off-by: Alistair Francis <[email protected]>
2019-09-30lib: Redirect WFI trapped from VS/VU mode to HS-modeAnup Patel
The WFI will trap as illegal instruction trap when executed in VS/VU mode so we just forward/redirect it to HS-mode so that hypervisor can deal with it appropriately. Signed-off-by: Anup Patel <[email protected]>
2019-09-30lib: Extend sbi_trap_redirect() for hypervisor extensionAnup Patel
When hypervisor extension is available, we can get traps from VS/VU modes. We should be able to force redirect some of these traps to HS-mode. In other words, we should be able forward traps from VS/VU mode to HS-mode using sbi_trap_redirect() hence this patch. Signed-off-by: Atish Patra <[email protected]> Signed-off-by: Anup Patel <[email protected]> Signed-off-by: Alistair Francis <[email protected]>
2019-09-30lib: Extend sbi_hart_switch_mode() to support hypervisor extensionAnup Patel
This patch extends sbi_hart_switch_mode() to support entering VS/VU modes when hypervisor extension is available. Signed-off-by: Anup Patel <[email protected]>
2019-09-30lib: Delegate supervisor ecall to HS-mode when H extension availableAnup Patel
When hypervisor extension is available, we only handle hypervisor ecalls coming from HS-mode and we let hypervisor handle ecalls coming from VS-mode. Signed-off-by: Anup Patel <[email protected]>
2019-09-28Write MSIP by using memory-mapped control registerZong Li
The machine-level MSIP bits are written by accesses to memory-mapped control registers. Only use CSR instruction for SSIP and USIP. There is no effect that using CSR instruction to write MSIP when testing on unleashed board and QEMU. Signed-off-by: Zong Li <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-09-10lib: provide a platform specific tlb range flush thresholdAtish Patra
Currently, the tlb range flush threshold is fixed and set to 4k for all platforms. However, it should be platform specific as it completely depends upon how platform actually implements sfence instruction. Define a platform feature that allows every individual platform to set different values. If a platform doesn't define it, just use a page size as the threshold. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Bin Meng <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-08-31lib: Upgrade to full flush if size is at least thresholdAtish Patra
Currently, we upgrade to a full tlb flush only If a tlb flush request size is greater than the threshold. This is done as sfence in RISC-V can only flush 4KB at a time. Doing a large number of flushes page by page impacts the performance. It is better to do a full tlbflush if the request size is at least equal to the threshold size. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-08-31lib: Support atomic swap instructionsAtish Patra
If compiler supports riscv atomic instructions, we should use them instead of legacy gcc built-in macros __sync_lock_test_and_set in atomic exchange functions. Signed-off-by: Atish Patra <[email protected]> Reviewed-by: Anup Patel <[email protected]>
2019-08-19Include `git describe` in OpenSBIPalmer Dabbelt
OpenSBI includes a version, but that is only updated when tagged. For users that are using the git releases we instead end up with an ambiguous version number, which makes it hard to figure out what everyone is using. This patch checks for a git directory and prints out the result of `git describe`, which is a mix of pretty and unambiguous. Signed-off-by: Palmer Dabbelt <[email protected]> Signed-off-by: Anup Patel <[email protected]> Reviewed-by: Bin Meng <[email protected]> Tested-by: Bin Meng <[email protected]>
2019-08-16lib: Fix race conditions in tlb fifo access.Atish Patra
Linux kernel expects tlb flush SBI call to be completely synchronous i.e. the SBI call should only return once corresponding *fence* instruction is executed. OpenSBI manages the outstanding TLB flush requests by keeping them in a per hart based fifo. However, there are few corner cases that may lead to race conditions while updating the fifo. Currently, the caller hart waits for IPI acknowledgement via clint address which is not a very good method as synchronization on MMIO may not be supported in every platform. Moreover, the waiter doesn't have any way of identifying if the IPI is received for specific tlb flush request or any other IPI. This may lead to unpredictable behavior in supervisor/user space. Fix this by waiting on individual fifo entries rather than MMIO address. Currently, a relaxed loop is being used because wfi again involves MMIO write which would be slower compared to relaxed loop. To avoid deadlock, fifo is processed every time a hart loops for fifo enqueue or fifo sync to consume the tlb flush requests sent by other harts. Signed-off-by: Anup Patel <[email protected]> Signed-off-by: Atish Patra <[email protected]>
2019-08-16lib: Provide an atomic exchange function unsigned longAtish Patra
Signed-off-by: Anup Patel <[email protected]> Signed-off-by: Atish Patra <[email protected]>
2019-08-13lib: Handle traps when doing unpriv load/store in get_insn()Anup Patel
We can get a page/access trap when doing unpriv load/store in get_insn() function because on a SMP system Linux swapper running on HART A can unmap pages from page table used by HART B. To tackle this we extend get_insn() implementation so that if we get trap in get_insn() then we redirect it to S-mode as fetch page/access fault. Signed-off-by: Anup Patel <[email protected]>
2019-08-12lib: Correct null pointer checkJacob Garber
In order to prevent a possible null pointer dereference, return early if either one of 'in' or 'data' is null. Signed-off-by: Jacob Garber <[email protected]> Reviewed-by: Bin Meng <[email protected]> Reviewed-by: Atish Patra <[email protected]>
2019-08-12lib: Prevent unintended sign extensionsJacob Garber
In the last argument to sbi_memset() we essentially have the following multiplication: size_t = u16 * u16 Due to C's integer semantics, both u16's are implicitly converted to int before the multiplication, which cannot hold all possible values of a u16 * u16. If the multiplication overflows, the intermediate result will be a negative number. On 64-bit platforms, this will be sign-extended to a huge integer in the conversion to a u64 (aka size_t). Being the size argument to sbi_memset(), this could potentially cause a large out-of-bounds write. The solution is to manually cast one of the u16 to a size_t, which will make it large enough to avoid the implicit conversion and any overflow. Signed-off-by: Jacob Garber <[email protected]> Reviewed-by: Bin Meng <[email protected]> Reviewed-by: Atish Patra <[email protected]>
2019-08-12lib: Use bitwise & instead of boolean &&Jacob Garber
!(mipval && MIP_MSIP) simplifies to !mipval, which checks if the entire variable is zero, not just a single bit. Fix this to use bitwise & instead. Signed-off-by: Jacob Garber <[email protected]> Reviewed-by: Bin Meng <[email protected]> Reviewed-by: Atish Patra <[email protected]>
2019-08-09lib: Use sbi_dprintf() for invalid CSRsAnup Patel
We should sbi_dprintf() instead of sbi_printf() for invalid CSRs because we are forwarding invalid CSR access back to S-mode. Signed-off-by: Anup Patel <[email protected]> Reviewed-by: Bin Meng <[email protected]>
2019-08-09lib: Introduce sbi_dprintf() APIAnup Patel
This patch introduces new sbi_dprintf() API for runtime debug prints. The sbi_dprintf() will print to console for a given HART only when SBI_SCRATCH_DEBUG_PRINTS option in enabled in sbi_scratch for this HART. We can now add debug prints using sbi_dprintf() at important places in OpenSBI sources. These debug prints will only show up when previous booting stage or compile time parameter sets the SBI_SCRATCH_DEBUG_PRINTS option in scratch space. Signed-off-by: Anup Patel <[email protected]> Reviewed-by: Bin Meng <[email protected]>
2019-07-26lib: Allow compiling without FP supportAnup Patel
Currently, we mandate 'F' and 'D' extension in riscv_fp.h so that misaligned load/store emulation has access to FP registers. The above is too restrictive and we should certainly allow compilation for soft-FP toolchains and explicit PLATFORM_RISCV_ISA not having 'F' and 'D' extensions. This patch extends riscv_fp.h and misaligned load/store emulation to allow compiling OpenSBI without FP support. Signed-off-by: Anup Patel <[email protected]> Reviewed-by: Bin Meng <[email protected]>
2019-06-19lib: Rename string.x to sbi_string.xAtish Patra
All string functions are part of libsbi. It makes more sense to rename them to sbi_string.x as the libsbi can be linked with external libraries that can have similar implementation. Signed-off-by: Atish Patra <[email protected]> Acked-by: Anup Patel <[email protected]>
2019-06-19lib: Include helper libc functions directly in libsbi.Atish Patra
libsbi needs some of the custom libc functions. It should be directly included in libsbi instead of platform specific libraries. Signed-off-by: Atish Patra <[email protected]> Acked-by: Anup Patel <[email protected]>
2019-06-19lib: Move sbi core library to lib/sbiAtish Patra
Signed-off-by: Atish Patra <[email protected]> Acked-by: Anup Patel <[email protected]>