template-pd: introduce 'template' attribute in sdf - #1
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| continue; | ||
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| void *src = (char *)ehdr + phdr[i].p_offset; | ||
| void *dest = (void *)(dest_vaddr + phdr[i].p_vaddr - ehdr->e_entry); |
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Unless this is a PIE exe you should only be loading an ELF at it's desired virtual address; this also seems to implicitly assume that the entry point is at the start of a PD's address space.
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So instead of forcing the clients to use PIE, I set up a region within the vspace of the template PD. The loadable segements (i.e., segs with PT_LOAD) of a payload should live within the given region. The payload is also required to begins at somewhere within the given region.
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| It also has the same attributes as protection domains but not: | ||
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| * `setvar_id`: This attribute is valid only when a program image is given. |
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is setvar_id an attribute on the child(?)
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Oh I think I have mistaken the usage of setvar_id, I will fix this
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Now it seems all setvars are disabled for templates. Tests are also provided.
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| void *src = (char *)ehdr + phdr[i].p_offset; | ||
| void *dest = (void *)(dest_vaddr + phdr[i].p_vaddr - ehdr->e_entry); |
This commmit allows users to create a type of PD that has no 'program_image'. Such a mechanism is helpful for loading application payloads into a microkit PD dynamically. The requirements of using a template PD are: - template PD should be a child PD of a PD who has no parent - template PD should not have children, VMs, program images - template PD should always be active (or their parents need to perform SchedContext unbound operations) Ref: - Ch.4., Evolving seL4CP Into a Dynamic OS, Leslie and Heiser, 2022 - https://trustworthy.systems/projects/microkit/2203-report-dynamic.pdf Signed-off-by: Guangtao Zhu <guangtaozhu@outlook.com>
Signed-off-by: Guangtao Zhu <guangtaozhu@outlook.com>
Setvar and setvars on elements within a template are all disabled, as they rely on a given program image, which is not provided when using a template PD. Signed-off-by: Guangtao Zhu <guangtaozhu@outlook.com>
midnightveil
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midnightveil
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Good enough for me :) There's some grammatical issues in some of the text but that's less important. Feel free to merge when desired.
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This commmit allows users to create a type of PD that has no 'program_image'. Such a mechanism is helpful for loading application payloads into a microkit PD dynamically.
The requirements of using a template PD are:
Something needs discussing is the PD information generated by microkit (e.g., pd_name, ppc bitmaps), which are not provided to the template PDs, as the template PDs have no program image to patch with.
This issue may affect the payloads that use libmicrokit as their runtime, which checks channel ids using the generated channel bitmaps.
A solution is adding a region to the image of the parent PD, which can and should record the microkit-generated PD information of the template PDs. We can provide an object file that contains a region, and put it in libmicrokit.a. PDs that use the region can conditionally link with the object file when building with libmicrokit. The parent PD can pass the microkit-generated info to the template PDs by patching the payload during late-loading.
Ref:
Redirected from: seL4#582