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Next patch will move all calls to riscv_load_initrd() to riscv_load_kernel(). Machines that want to load initrd will be able to do via an extra flag to riscv_load_kernel(). This change will expose a sign-extend behavior that is happening in load_elf_ram_sym() when running 32 bit guests [1]. This is currently obscured by the fact that riscv_load_initrd() is using the return of riscv_load_kernel(), defined as target_ulong, and this return type will crop the higher 32 bits that would be padded with 1s by the sign extension when running in 32 bit targets. The changes to be done will force riscv_load_initrd() to use an uint64_t instead, exposing it to the padding when dealing with 32 bit CPUs. There is a discussion about whether load_elf_ram_sym() should or should not sign extend the value returned by 'lowaddr'. What we can do is to prevent the behavior change that the next patch will end up doing. riscv_load_initrd() wasn't dealing with 64 bit kernel entries when running 32 bit CPUs, and we want to keep it that way. One way of doing it is to use target_ulong in 'kernel_entry' in riscv_load_kernel() and rely on the fact that this var will not be sign extended for 32 bit targets. Another way is to explictly clear the higher 32 bits when running 32 bit CPUs for all possibilities of kernel_entry. We opted for the later. This will allow us to be clear about the design choices made in the function, while also allowing us to add a small comment about what load_elf_ram_sym() is doing. With this change, the consolation patch can do its job without worrying about unintended behavioral changes. [1] https://lists.gnu.org/archive/html/qemu-devel/2023-01/msg02281.html Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20230206140022.2748401-2-dbarboza@ventanamicro.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> |
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| authz | ||
| block | ||
| chardev | ||
| crypto | ||
| disas | ||
| exec | ||
| fpu | ||
| hw | ||
| io | ||
| libdecnumber | ||
| migration | ||
| monitor | ||
| net | ||
| qapi | ||
| qemu | ||
| qom | ||
| scsi | ||
| semihosting | ||
| standard-headers | ||
| sysemu | ||
| tcg | ||
| ui | ||
| user | ||
| elf.h | ||
| glib-compat.h | ||
| qemu-io.h | ||
| qemu-main.h | ||