drivers: add ramdisk storage driver
#2096
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| return irangel(e->base, e->length); | ||
| } | ||
| return irange(INVALID_PHYSICAL, INVALID_PHYSICAL); | ||
| } |
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Instead of having this function defined in all architectures, it's better to pass the ramdisk range directly to init_ramdisk() as a function argument, and call init_ramdisk() only when there is an actual ramdisk.
| token = runtime_strtok_r(&input, delim, &rest); | ||
| while (!sstring_is_null(token)) { | ||
| if(runtime_strcmp(token, ss("verbose")) == 0) { | ||
| cmdline_verbose_logging = true; |
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I would remove the cmdline_verbose_logging variable, and keep logging confined to when INIT_DEBUG is #defined; after all, these logging messages are useful mostly when debugging, and I would rather avoid carrying this debug stuff in production kernels.
| storage, st, boolean, write, | ||
| void *buf, range blocks, status_handler sh); | ||
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| typedef struct storage |
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Better to avoid such a generic name, I would add a ramdisk-related prefix, e.g. something like struct ramdisk_storage
| { | ||
| closure_struct(storage_simple_req_handler, req_handler); | ||
| closure_struct(ramdisk_io, read); | ||
| closure_struct(ramdisk_io, write); |
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It's not necessary to define the ramdisk_io closure struct, you can use closure_struct(block_io) instead, for both read and write. Then, you can have 2 separate functions (defined with closure_func_basic) for read and write: for reading, you would retrieve the ramdisk_storage struct pointer via struct_from_closure(); for writing, you don't need any pointer and just apply the status handler with the error status.
| u64 end_byte_offset = blocks.end * SECTOR_SIZE; | ||
| if (start_byte_offset > end_byte_offset || end_byte_offset > st->ramdisk_size) | ||
| { | ||
| apply(sh, timm("result", "read out of bounds")); |
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Can use range_valid(blocks); also, instead of applying an error status to the status handler, I would just use assert(), since an out-of-bounds range would indicate a kernel bug bad enough to warrant taking down the VM.
| return; | ||
| } | ||
| u64 ramdisk_size = range_span(ramdisk_phys); | ||
| u64 v = allocate_u64((heap)heap_virtual_huge(kh), ramdisk_size); |
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assert(v != INVALID_PHYSICAL);
| map(v, ramdisk_phys.start, ramdisk_size, pageflags_memory()); | ||
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| heap h = heap_locked(kh); | ||
| storage st = allocate(h, sizeof(struct storage)); |
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assert(st != INVALID_ADDRESS);
| init_closure(&st->read, ramdisk_io, st, false), | ||
| init_closure(&st->write, ramdisk_io, st, true)), | ||
| ramdisk_size, -1); | ||
| msg_print("RAMDISK: %u bytes at %p", st->ramdisk_size, st->ramdisk); |
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Better to use msg_info(). For most things the kernel is quiet during boot, unless explicitly told to be more verbose. (I know, right now LOG_INFO messages cannot be enabled this early during boot, but hopefully we will add this capability in the future.)
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| _start: | ||
| xor edx, edx |
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Should be xor rdx, rdx, so that all 64 bits are zeroed.
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This patch adds support for using the kernel ramdisk as read-only block storage.